RFR: 8318839: Update test thread factory to catch all exceptions

[Leonid Mesnik]

The jtreg starts the main thread in a separate ThreadGroup and checks unhandled exceptions for this group. However, it doesn't catch all unhandled exceptions. There is a jtreg issue for this https://bugs.openjdk.org/browse/CODETOOLS-7903526.
Catching such issues for virtual threads is important because they are not included in any groups. So this fix implements the handler for the test thread factory. 

A few tests start failing.

The test
serviceability/jvmti/HeapMonitor/MyPackage/HeapMonitorVMEventsTest.java
has testcases for platform and virtual threads. So, there is there's no need to run it with the thread factory.

The test
java/lang/Thread/virtual/ThreadAPI.java
tests UncaughtExceptionHandler and virtual threads. No need to run it with a thread factory.

Test 
test/jdk/java/util/concurrent/tck/ThreadTest.java is updated to not check the default empty handler.

Probably, we need some common approach about dealing with the UncaughtExceptionHandler in jtreg.

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Commit messages:
 - 8318839: Update test thread factory to catch all exceptions

Changes: https://git.openjdk.org/jdk/pull/16369/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16369&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318839
  Stats: 18 lines in 4 files changed: 15 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/16369.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16369/head:pull/16369

PR: https://git.openjdk.org/jdk/pull/16369