RFR: 8287596: Reorg jdk.test.lib.util.ForceGC [v11]

[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 incrementally with one additional commit since the last revision:

  update per feedback

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/8979/files
  - new: https://git.openjdk.org/jdk/pull/8979/files/0f196282..31dffa98

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=8979&range=10
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=8979&range=09-10

  Stats: 5 lines in 1 file changed: 1 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/8979.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/8979/head:pull/8979

PR: https://git.openjdk.org/jdk/pull/8979