ci: twister: Add --specs to ccache ignore option list

This commit adds the compiler `--specs=*` flag to the ccache ignore option
list because ccache is unable to resolve the toolchain-provided specs file
path and will consider source files to be uncacheable if it is unable to
read the specified specs file.

Note that adding `--specs=*` to the ignore option list is not a problem
because it is unlikely for the content of the toolchain libc spec file to
change without the compiler executable itself changing.

Signed-off-by: Stephanos Ioannidis <[email protected]>

Author: stephanosio

.github/workflows/twister.yaml

@@ -146,6 +146,8 @@ jobs:
     env:
       CCACHE_DIR: /node-cache/ccache-zephyr
       CCACHE_REMOTE_STORAGE: "redis://cache-*.keydb-cache.svc.cluster.local|shards=1,2,3"
+      # `--specs` is ignored because ccache is unable to resovle the toolchain specs file path.
+      CCACHE_IGNOREOPTIONS: '--specs=*'
       BSIM_OUT_PATH: /opt/bsim/
       BSIM_COMPONENTS_PATH: /opt/bsim/components
       TWISTER_COMMON: ' --force-color --inline-logs -v -N -M --retry-failed 3 '