[FLINK-37247][FileSystems][Tests] Implement common Hadoop file system integration tests for GCS.

[cnauroth]

What is the purpose of the change

Increase test coverage for GCS integration by providing integration tests implemented from the common flink-hadoop-fs test suites. These optional tests run only if the environment is configured for access to GCS.

Brief change log

• Create JUnit extension RequireGCSConfiguration. The extension checks for environment variables GOOGLE_APPLICATION_CREDENTIALS and GCS_BASE_PATH. If these are not defined, then the tests are skipped.
• Create GCS subclasses of the suites defined in flink-hadoop-fs.
• Two tests needed to be overridden in the subclasses and skipped. One isn't meaningful for GCS and triggers a false failure. The other is going to take a lot more intrusive changes to get working on GCS because of an assumption that state is held in exactly one file, which isn't true for the GCS implementation.
• Allow RecoverableWriter tests to return null from getLocalTmpDir() to indicate no allocation/release of local storage is required.
• A new ArchUnit exception is added, because these integration tests can't meaningfully use the mini-cluster extensions. This is similar to how it's handled for other file systems.

Verifying this change

This change added tests and can be verified as follows:

New integration tests are skipped when run without setting the configuration, so there is no impact to existing developer workflows:

mvn -Pfast -pl flink-filesystems/flink-gs-fs-hadoop clean verify
...
[INFO] Tests run: 0, Failures: 0, Errors: 0, Skipped: 0
...

With configuration in place, the tests pass (with the exception of the two that are skipped):

export GOOGLE_APPLICATION_CREDENTIALS=/tmp/credentials.json
export GCS_BASE_PATH=gs://<BUCKET>/flink-tests
mvn -Pfast -pl flink-filesystems/flink-gs-fs-hadoop clean verify
...
[WARNING] Tests run: 35, Failures: 0, Errors: 0, Skipped: 2
...

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

[flinkbot]

CI report:

• f1f2bce Azure: SUCCESS

Bot commands

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[cnauroth]

I pushed up a change, running mvn spotless:apply to fix the style violations.

The test failures appear to be unrelated.

[cnauroth]

Hello @MartijnVisser . Are you available for a code review?

I'm planning on sending another pull request later for another GCS connector version upgrade. It would be nice to have these new tests in place in a known working state first.

Thanks!