RFR: 8253833: mutexLocker assert_locked_or_safepoint should not access VMThread state from non-VM-thread

[Robbin Ehn]

It's unsafe for all threads except VM thread to access the current vm operation.
This part of the assert is also faulty:
If we are not at safepoint and the operation requester (calling thread) would be the owner of the lock do not mean it
is safe for current thread.

Passes t1-5. (also note VMThread::vm_operation() assert current thread is VM thread, and I have seen no such assert)

Thanks

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

Commit messages:
 - Removed vm op caller check

Changes: https://git.openjdk.java.net/jdk/pull/563/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=563&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253833
  Stats: 3 lines in 1 file changed: 0 ins; 3 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/563.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/563/head:pull/563

PR: https://git.openjdk.java.net/jdk/pull/563