Bump Java runtime tests to Java 21.

[copybara-service[bot]]

Bump Java runtime tests to Java 21.

Fixed exclude test file:

• Removed tests which were removed in this new version.
• Add broken tests as broken.
• Fixed marking of broken tests in existing list.
• Un-excluded tests which are now passing with gVisor.
• Added tests which fail with gVisor.
• Ran flaky tests 20x times before removing from exclude list.