Should fix "Expiring Daemon because JVM heap space is exhausted".
https://github.com/grpc/grpc-java/pull/9269 probably pushed the build
over the edge, but there's been evidence via flakes for a good while
that we've been reaching the limit.
b/238334438
This Addresses the issue with skips not working due to the
missing/inconsistent `--testing_version` flag, ref b/235688697.
1. Uses the new `TESTING_VERSION` variable populated in the shared
grpc_xds_k8s_install_test_driver.sh - new approach for detecting
versions applicable to all languages.
2. Use `TESTING_VERSION` in all build files in `--testing_version` and
when tagging docker images. This will be backported to all active
test branches. Build Scripts in all other languages will be updated
as well.
Corresponding grpc core change: https://github.com/grpc/grpc/pull/30027
Related PR grpc/grpc#26764
Related CL cl/386366746
This test suite will be run every 6 hours, and takes around 30 minutes. The script is copied from xds-k8s.sh, and removed the generation of server image.