test/kokoro: simplify PSM Interop Kokoro buildscripts

[sergiitk]

Integrates the new features of the the Kokoro PSM Interop install library introduced in grpc/psm-interop#73.

Nearly all common functionality was moved from per-language/per-branch PSM Interop build scripts to psm_interop_kokoro_lib.sh:

1. The list of tests in the each test suite
2. Per-test-suite flag customization
3. run_test methods
4. build_docker_images_if_needed methods
5. Generic build_test_app_docker_images methods (simple docker build + docker push + docker tag). grpc-java is one exception, as it doesn't run docker directly, but a cloudbuild flow.

Now all PSM Interop jobs share the same buildscripts by all test suites:

1. buildscript that invokes the test: psm-interop-test-{language}.sh (configured as build_file in the build cfg)
2. buildscript that builds the xDS test client/server and publishes them as a Docker image: psm-interop-build-{language}.sh (conventional name called from psm_interop_kokoro_lib.sh)

psm-interop-test-{language}.sh:

1. Sets GRPC_LANGUAGE, BUILD_SCRIPT_DIR environment variables.
2. Downloads the shared psm_interop_kokoro_lib.sh from the main branch of the psm-interop repo.
3. Sources psm-interop-build-{language}.sh
4. Calls psm::run "${PSM_TEST_SUITE}" (PSM_TEST_SUITE configured in the cfg file).

psm-interop-build-{language}.sh:

1. Defines psm::lang::build_docker_images which is called from psm_interop_kokoro_lib.sh.
2. Invokes any repo-specific logic.
3. May use psm::build::docker_images_generic for generic Docker build, tag, push, or provide implement its own build/publish method.

References:

• b/288578634
• See the full list of the new features at Move all common buildscript functionality to psm_interop_kokoro_lib.sh psm-interop#73.
• Additional fixes to the shared lib: kokoro: Call 'docker push' correctly while pushing images psm-interop#78, Shared kokoro lib: address feedback psm-interop#79

RELEASE NOTES: n/a

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.54%. Comparing base (adf976b) to head (15a33a7).
Report is 35 commits behind head on master.

❗ Current head 15a33a7 differs from pull request most recent head 113ae98. Consider uploading reports for the commit 113ae98 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7171      +/-   ##
==========================================
- Coverage   81.24%   80.54%   -0.70%     
==========================================
  Files         345      347       +2     
  Lines       33941    33991      +50     
==========================================
- Hits        27574    27379     -195     
- Misses       5202     5423     +221     
- Partials     1165     1189      +24     

see 25 files with indirect coverage changes

[sergiitk]

Using grpc/psm-interop#73 / grpc/psm-interop@c55e0b1:

• grpc/go/master/branch/xds_k8s_lb
• grpc/go/master/branch/psm-security
• grpc/go/master/branch/xds_url_map

[sergiitk]

Using grpc/psm-interop#73 / grpc/psm-interop@5aeb13f:

Full LB test run.

• grpc/go/master/branch/xds_k8s_lb

[arvindbr8]

Seems like the tests pass. @sergiitk - Looks good to me. I can approve when you send the PR out for review.

[sergiitk]

@arvindbr8 Thank you. This depends on grpc/psm-interop#73. Once it's merged, I'll promote this PR from a draft.

[sergiitk]

The last check using the install script from main:

• grpc/go/master/branch/psm-security
• grpc/go/master/branch/xds_k8s_lb
• grpc/go/master/branch/xds_url_map

[sergiitk]

@arvindbr8 please review, but don't merge it yet. I'd like to wait until I got approvals on the same change from the rest of the repos. So we don't have to do another set of backports if anything comes up.

[arvindbr8]

Sure will do once the tests pass. Do you mind re-assigning this to me when you think it's ready?

[sergiitk]

Using grpc/psm-interop@2cbdfd02 (main).

• grpc/go/master/branch/xds_k8s_lb
• grpc/go/master/branch/psm-security
• grpc/go/master/branch/xds_url_map