RFR: 8366692: Several gc/shenandoah tests timed out [v2]

[SendaoYan]

> Hi all,
> 
> After JDK-8260555 set the default jtreg timeout factor to 1, then several gc/shenandoah tests run timed out with jtreg options -timeoutFactor:1. So I think it's necessary to increase the timeout value set in tests to make test run normally.
> 
> The actual run time consumed on my linux-x64 machine with  224 CPU core threads shows in [JDK-8366692](https://bugs.openjdk.org/browse/JDK-8366692).
> 
> Accodring the time statistics, the test test/hotspot/jtreg/gc/shenandoah/TestSieveObjects.java only change the second `@run` at the `@test id=generational` and `@test id=aggressive`, other tests do not need to change. And all the `@run` in test test/hotspot/jtreg/gc/shenandoah/jni/TestJNIGlobalRefs.java changed from 120(default value) to 240.
> 
> Change has been verified locally on linux-x64, test-fix only, no risk.

SendaoYan has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Merge branch 'openjdk:master' into jbs8366692
 - add timeout value for @aggressive
 - 8366692: Several gc/shenandoah tests timed out

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/27052/files
  - new: https://git.openjdk.org/jdk/pull/27052/files/4d8a9601..c5e3ab20

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27052&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27052&range=00-01

  Stats: 831 lines in 41 files changed: 270 ins; 348 del; 213 mod
  Patch: https://git.openjdk.org/jdk/pull/27052.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27052/head:pull/27052

PR: https://git.openjdk.org/jdk/pull/27052