RFR: 8298853: JvmtiVTMSTransitionDisabler should support disabling one virtual thread transitions [v6]

[Serguei Spitsyn]

> Now the `JvmtiVTMSTransitionDisabler` mechanism supports disabling VTMS transitions for all virtual threads only. It should also support disabling transitions for any specific virtual thread as well. This will improve scalability of the JVMTI functions operating on target virtual threads as the functions can be executed concurrently without blocking each other execution when target virtual threads are different.
> New constructor `JvmtiVTMSTransitionDisabler(jthread vthread)` is added which has jthread parameter of the target virtual thread.
> 
> Testing:
>   mach5 jobs are TBD (preliminary testing was completed):
>    - all JVMTI, JDWP, JDI and JDB tests have to be run
>    - Kitchensink
>    - tier5

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

  minor comments are resolved

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11690/files
  - new: https://git.openjdk.org/jdk/pull/11690/files/3effc27d..146c2a59

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11690&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11690&range=04-05

  Stats: 4 lines in 1 file changed: 2 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/11690.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11690/head:pull/11690

PR: https://git.openjdk.org/jdk/pull/11690