Add docker test suite, include debian 12 to start

[lopcode]

Relates to #121

Output:

🥕 carrot 🗂  ~/git/vips-ffm 🐙 task/docker-debian-12 $ ./run_docker_tests.sh
building samples...

Deprecated Gradle features were used in this build, making it incompatible with Gradle 9.0.

You can use '--warning-mode all' to show the individual deprecation warnings and determine if they come from your own scripts or plugins.

For more on this, please refer to https://docs.gradle.org/8.10.1/userguide/command_line_interface.html#sec:command_line_warnings in the Gradle documentation.

BUILD SUCCESSFUL in 615ms
6 actionable tasks: 2 executed, 2 from cache, 2 up-to-date
running docker tests...
~/git/vips-ffm/docker_tests/debian-12 ~/git/vips-ffm
[+] Building 0.1s (13/13) FINISHED                                                                                                                docker:desktop-linux
 => [internal] load build definition from Dockerfile                                                                                                              0.0s
 => => transferring dockerfile: 327B                                                                                                                              0.0s
 => WARN: JSONArgsRecommended: JSON arguments recommended for CMD to prevent unintended behavior related to OS signals (line 12)                                  0.0s
 => [internal] load metadata for docker.io/library/eclipse-temurin:22                                                                                             0.0s
 => [internal] load metadata for docker.io/library/debian:12.1-slim                                                                                               0.0s
 => [internal] load .dockerignore                                                                                                                                 0.0s
 => => transferring context: 2B                                                                                                                                   0.0s
 => FROM docker.io/library/eclipse-temurin:22                                                                                                                     0.0s
 => [internal] load build context                                                                                                                                 0.1s
 => => transferring context: 16.91MB                                                                                                                              0.1s
 => [stage-0 1/6] FROM docker.io/library/debian:12.1-slim                                                                                                         0.0s
 => CACHED [stage-0 2/6] COPY --from=eclipse-temurin:22 /opt/java/openjdk /opt/java/openjdk                                                                       0.0s
 => CACHED [stage-0 3/6] COPY sample /opt/sample                                                                                                                  0.0s
 => CACHED [stage-0 4/6] COPY run_samples.sh /opt/run_samples.sh                                                                                                  0.0s
 => CACHED [stage-0 5/6] RUN apt update && apt install libvips-dev -y                                                                                             0.0s
 => CACHED [stage-0 6/6] WORKDIR /opt                                                                                                                             0.0s
 => exporting to image                                                                                                                                            0.0s
 => => exporting layers                                                                                                                                           0.0s
 => => writing image sha256:afae013a770faba7a140f5b3dd6bc8e4ef0f3e6e34967d71393fa2dc87737a18                                                                      0.0s
 => => naming to docker.io/library/vips-ffm-debian-test                                                                                                           0.0s

 1 warning found (use docker --debug to expand):
 - JSONArgsRecommended: JSON arguments recommended for CMD to prevent unintended behavior related to OS signals (line 12)

What's next:
    View a summary of image vulnerabilities and recommendations → docker scout quickview 
skipping sample build as no gradle present...
running samples...
[main] INFO vipsffm.SampleRunner - running sample "RawGetVersionSample"...
[main] INFO vipsffm.sample.RawGetVersionSample - libvips version: "8.14.1"
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "HelperGetVersionSample"...
[main] INFO vipsffm.sample.HelperGetVersionSample - libvips version: "8.14.1"
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VImageCreateThumbnailSample"...
[main] INFO vipsffm.sample.VImageCreateThumbnailSample - source image size: 2490 x 3084
[main] INFO vipsffm.sample.VImageCreateThumbnailSample - thumbnail image size: 323 x 400
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VImageChainSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VSourceTargetSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VImageCopyWriteSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VOptionHyphenSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VImageCachingSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VImageBlobSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VImageArrayJoinSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VBlobByteBufferSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VTargetToFileSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VImageJoinSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VImageFromBytesSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - running sample "VImageStreamSample"...
[main] INFO vipsffm.SampleRunner - validation succeeded ?
[main] INFO vipsffm.SampleRunner - shutting down vips to check for memory leaks...
memory: high-water mark 150.01 MB
[main] INFO vipsffm.SampleRunner - all samples ran successfully ?
vips_threadset_free: peak of 17 threads
checking for leaks...
no leaks detected 🎉