[AMORO-4303][AMS] Stabilize optimizer heartbeat tests

[johntomcat7408-cmyk]

Why are the changes needed?

Close #4303.

AMSServiceTestBase applied an 800 ms optimizer heartbeat timeout to every optimizer test, while its background toucher only attempted a heartbeat every 300 ms. Under CI scheduling or database delays, tests that were not exercising expiration could lose the optimizer, requeue its task, and fail nondeterministically.

Brief change log

• Use a 10-second heartbeat timeout for ordinary optimizer tests while retaining an explicit 800 ms timeout in expiration-specific tests.
• Touch every 100 ms and replace fixed sleeps with condition-based waits for task and optimizer state transitions.
• Fully dispose and restore test services around custom-timeout scenarios so background keepers cannot leak between tests.
• Ignore keeper failures only after shutdown has begun, while preserving runtime error logging.

How was this patch tested?

• Update the existing optimizer service tests to cover normal and expiration-specific timing independently.
• Add screenshots for manual tests if appropriate (not applicable).
• Run tests locally before making a pull request.

Validation performed against commit 7efadacadc3561b60ec7c10cc28e91964c29e5a8:

• JDK 11: full TestDefaultOptimizingService suite (22 tests) passed, followed by 20/20 successful repetitions of testPollTaskThreeTimes.
• JDK 17: full TestDefaultOptimizingService suite (22 tests) passed, followed by 20/20 successful repetitions of testPollTaskThreeTimes.
• Spotless, Checkstyle, production compilation, and test compilation passed.

Documentation

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