RFR: 8365192: post_meth_exit should be in vm state when calling get_jvmti_thread_state [v6]

[Leonid Mesnik]

> The method
> get_jvmti_thread_state()
> should be called only while thread is in vm state.
> 
> The post_method_exit is doing some preparation before switching to vm state. This cause issues if thread is needed to initialize jvmti thread state.
> 
> The fix was found using jvmti stress agent and thus no additional regression test is required.

Leonid Mesnik has updated the pull request incrementally with three additional commits since the last revision:

 - moved JRT_BLOCK
 - added assertion and removed comment.
 - test fixed.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26713/files
  - new: https://git.openjdk.org/jdk/pull/26713/files/d9d21af6..32b08587

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26713&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26713&range=04-05

  Stats: 34 lines in 3 files changed: 14 ins; 7 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/26713.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26713/head:pull/26713

PR: https://git.openjdk.org/jdk/pull/26713