[#1675][FOLLOWUP] fix(test): Explicitly close resources to avoid unexcepted behaviors

[rickyma]

What changes were proposed in this pull request?

Fix various flaky tests:

1. After using ApplicationManager, release resources at once, which will let ScheduledExecutorService work background to cause unexpected behaviors.
2. Release DynamicClientConfService after using it.
3. Release SimpleClusterManager everytime after using it. Since the execution order of JUnit test methods is random, unless we specifically set the execution order. So it is better not to initialize the SimpleClusterManager object globally.
4. Wait for a while to ensure the port is released in UniffleJavaProcess.
5. Always call stopServer after new CoordinatorServer() to shut down multiple ExecutorService from running in background, which could cause unexpected behaviors.

Why are the changes needed?

For #1675.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Unnecessary.

[github-actions]

Test Results

 2 419 files  ±0   2 419 suites  ±0   5h 1m 14s ⏱️ + 3m 21s
   933 tests ±0     932 ✅ ±0   1 💤 ±0  0 ❌ ±0 
10 819 runs  ±0  10 805 ✅ ±0  14 💤 ±0  0 ❌ ±0 

Results for commit 8fc9f02. ± Comparison against base commit a0e88da.

[zuston]

LGTM. Thanks for your effort for the better + stable tests.

Although it looks a bit wire for every resource manager to be wrapped in the try . (Java lacks the drop semantic.)