RFR: 8287596: Reorg jdk.test.lib.util.ForceGC [v7]

[Xue-Lei Andrew Fan]

> This is a follow up update per comments in [JDK-8287384 PR](https://github.com/openjdk/jdk/pull/8907).  The tier1 and tier2 test in open part looks good to me.  Please help to run Mach5 just case the closed test cases are impacted.

Xue-Lei Andrew Fan has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains ten commits:

 - Merge
 - Merge master
 - Merge
 - add timeout parameter
 - rollback is not in this branch
 - rollback JDK-8287384
 - back to wait 1 second
 - Remove trailing white space
 - 8287596: Reorg jdk.test.lib.util.ForceGC

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Changes: https://git.openjdk.java.net/jdk/pull/8979/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8979&range=06
  Stats: 86 lines in 10 files changed: 12 ins; 29 del; 45 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8979.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8979/head:pull/8979

PR: https://git.openjdk.java.net/jdk/pull/8979