RFR: 8319897: Move StackWatermark handling out of LockStack::contains [v2]

[Stefan Karlsson]

> There are StackWatermark handling inside LockStack::contains. This is an indication that either:
> 1) some thread has failed to start it's own StackWatermark processing, or
> 2) that some thread is looking into the oops of another thread without starting the StackWatermark handling. The latter is usually more common.
> 
> I propose that we hoist the StackWatermark processing out of the LockStack into the code that actually performs pokes around in other thread's data. This is usually where we put the StackWatermark processing calls.
> 
> Note: that this doesn't fix a bug, it merely moves the processing code nearer the source of the problematic calls. I've found that jmm_GetThreadInfo looks straight into running thread's lock stacks without while those threads are running. That is a race that we should get rid of and I've created [JDK-8319899](https://bugs.openjdk.org/browse/JDK-8319899) for that issue.

Stefan Karlsson has updated the pull request incrementally with one additional commit since the last revision:

  Stream line the assert

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/16609/files
  - new: https://git.openjdk.org/jdk/pull/16609/files/63db2085..e8f71114

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16609&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16609&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/16609.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16609/head:pull/16609

PR: https://git.openjdk.org/jdk/pull/16609