[AMORO-3853] Stabilize continuous optimizing tests on Java 17

[xxubai]

Why are the changes needed?

Some continuous optimizing tests are unstable on Java 17 due to non-deterministic test data generation and missing test build configuration for generated sources.

Follow #3853.

Brief change log

• make RandomRecordGenerator deterministic for the affected test flows
• update keyed/unkeyed continuous optimizing tests to use the deterministic seed
• exclude src/main/gen-java/** from checkstyle in amoro-common
• keep surefire configured in amoro-common for test execution

How was this patch tested?

• Add some test cases that check the changes thoroughly including negative and positive cases if possible
• Add screenshots for manual tests if appropriate
• Run test locally before making a pull request

Local verification:

• ./mvnw -pl amoro-ams -am -Dtest=TestKeyedContinuousOptimizing,TestUnKeyedContinuousOptimizing test

Documentation

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

[zhoujinsong]

The fix is correct — the root cause is that randomRecord() was creating a new Random() on every call, completely bypassing the seed passed to the constructor. The other changes (UUID generation, fixed base timestamps) are also necessary to achieve full determinism.

Minor nit: truncatedTo(ChronoUnit.MICROS) after .plusNanos(random.nextInt(1_000_000) * 1_000L) is redundant since the result is already microsecond-aligned. Not a blocker.

LGTM.

[xxubai]

Thanks @zhoujinsong