RFR: 8316682: serviceability/jvmti/vthread/SelfSuspendDisablerTest timed out [v2]

[Serguei Spitsyn]

> This fixes the issue with lack of synchronization between JVMTI thread suspend and resume functions in a self-suspend case. More detailed fix description is in the first PR comment.
> 
> Testing: Ran mach5 tiers 1-6.

Serguei Spitsyn has updated the pull request incrementally with one additional commit since the last revision:

  some cleanup

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/24269/files
  - new: https://git.openjdk.org/jdk/pull/24269/files/f1fb7905..18944347

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24269&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24269&range=00-01

  Stats: 9 lines in 2 files changed: 0 ins; 8 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/24269.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24269/head:pull/24269

PR: https://git.openjdk.org/jdk/pull/24269