[jdk25u] RFR: 8370732: Use WhiteBox.getWhiteBox().fullGC() to provoking gc for nsk/jvmti tests [v2]

[SendaoYan]

> Hi all,
> 
> This pull request contains a backport of commit [54fe5021](https://github.com/openjdk/jdk/commit/54fe50210efe9ae6fad225b815cfdeb16c868115) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.
> 
> The commit being backported was authored by SendaoYan on 1 Nov 2025 and was reviewed by Chris Plummer, Leonid Mesnik and Serguei Spitsyn.
> 
> Thanks!

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 two additional commits since the last revision:

 - Merge branch 'openjdk:master' into backport-sendaoYan-54fe5021-master
 - Backport 54fe50210efe9ae6fad225b815cfdeb16c868115

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

Changes:
  - all: https://git.openjdk.org/jdk25u/pull/353/files
  - new: https://git.openjdk.org/jdk25u/pull/353/files/43b0324e..6273c34c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk25u&pr=353&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk25u&pr=353&range=00-01

  Stats: 75 lines in 10 files changed: 63 ins; 1 del; 11 mod
  Patch: https://git.openjdk.org/jdk25u/pull/353.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u.git pull/353/head:pull/353

PR: https://git.openjdk.org/jdk25u/pull/353