chore: introduce .kokoro templates for GraalVM jobs (#3737)

Context: [we will introduce a new GraalVM
job](https://docs.google.com/document/d/1bOeGtVFLsq5ts71If5pFXCvHIeNpbtBRvF6XQfavLZs/edit?tab=t.dcjxhf429j6t#bookmark=id.3s7d4dj247hr)
and will leverage the hermetic build templates to propagate this change
to some of the repositories. Each PR will be followed with ad-hoc
changes such as sync-repo-settings (the cannot be templated).

Demo PRs
 * googleapis/java-bigtable#2558
 * googleapis/java-bigquerystorage#2937
 * googleapis/java-storage#3029
 * googleapis/java-datastore#1816
* There are manual changes in `build.sh`. We will add this file to the
[ignored files in
owlbot.py](https://github.com/googleapis/java-datastore/blob/8ceb62b5182e30b4f771d6c1b586a22fb084c9ac/owlbot.py#L48-L57)
and will raise an issue to move this logic elsewhere (if feasible).
 * googleapis/java-firestore#2074
 * googleapis/java-logging#1789
 * googleapis/java-pubsub#2389
 * googleapis/java-pubsublite#1839
 * googleapis/java-spanner#3821

Author: diegomarquezp

hermetic_build/library_generation/owlbot/templates/java_library/.kokoro/presubmit/graalvm-a.cfg

@@ -0,0 +1,38 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Configure the docker image for kokoro-trampoline.
+env_vars: {
+  key: "TRAMPOLINE_IMAGE"
+  value: "gcr.io/cloud-devrel-public-resources/graalvm_sdk_platform_b:3.45.1"
+}
+
+env_vars: {
+  key: "JOB_TYPE"
+  value: "graalvm"
+}
+
+# TODO: remove this after we've migrated all tests and scripts
+env_vars: {
+  key: "GCLOUD_PROJECT"
+  value: "gcloud-devel"
+}
+
+env_vars: {
+  key: "GOOGLE_CLOUD_PROJECT"
+  value: "gcloud-devel"
+}
+
+env_vars: {
+  key: "GOOGLE_APPLICATION_CREDENTIALS"
+  value: "secret_manager/java-it-service-account"
+}
+
+env_vars: {
+  key: "SECRET_MANAGER_KEYS"
+  value: "java-it-service-account"
+}
+
+env_vars: {
+  key: "IT_SERVICE_ACCOUNT_EMAIL"
+  value: "[email protected]"
+}

hermetic_build/library_generation/owlbot/templates/java_library/.kokoro/presubmit/graalvm-b.cfg

@@ -0,0 +1,38 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Configure the docker image for kokoro-trampoline.
+env_vars: {
+  key: "TRAMPOLINE_IMAGE"
+  value: "gcr.io/cloud-devrel-public-resources/graalvm_sdk_platform_b:3.45.1"
+}
+
+env_vars: {
+  key: "JOB_TYPE"
+  value: "graalvm"
+}
+
+# TODO: remove this after we've migrated all tests and scripts
+env_vars: {
+  key: "GCLOUD_PROJECT"
+  value: "gcloud-devel"
+}
+
+env_vars: {
+  key: "GOOGLE_CLOUD_PROJECT"
+  value: "gcloud-devel"
+}
+
+env_vars: {
+  key: "GOOGLE_APPLICATION_CREDENTIALS"
+  value: "secret_manager/java-it-service-account"
+}
+
+env_vars: {
+  key: "SECRET_MANAGER_KEYS"
+  value: "java-it-service-account"
+}
+
+env_vars: {
+  key: "IT_SERVICE_ACCOUNT_EMAIL"
+  value: "[email protected]"
+}

hermetic_build/library_generation/owlbot/templates/java_library/.kokoro/presubmit/graalvm-c.cfg

@@ -0,0 +1,38 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Configure the docker image for kokoro-trampoline.
+env_vars: {
+  key: "TRAMPOLINE_IMAGE"
+  value: "gcr.io/cloud-devrel-public-resources/graalvm_sdk_platform_b:3.45.1"
+}
+
+env_vars: {
+  key: "JOB_TYPE"
+  value: "graalvm"
+}
+
+# TODO: remove this after we've migrated all tests and scripts
+env_vars: {
+  key: "GCLOUD_PROJECT"
+  value: "gcloud-devel"
+}
+
+env_vars: {
+  key: "GOOGLE_CLOUD_PROJECT"
+  value: "gcloud-devel"
+}
+
+env_vars: {
+  key: "GOOGLE_APPLICATION_CREDENTIALS"
+  value: "secret_manager/java-it-service-account"
+}
+
+env_vars: {
+  key: "SECRET_MANAGER_KEYS"
+  value: "java-it-service-account"
+}
+
+env_vars: {
+  key: "IT_SERVICE_ACCOUNT_EMAIL"
+  value: "[email protected]"
+}