review for 7150390: JFR test crashed on assert(_jni_lock_count == count) failed: must be equal

[Tom Rodriguez]

http://cr.openjdk.java.net/~never/7150390
33 lines changed: 28 ins; 4 del; 1 mod; 7748 unchg

7150390: JFR test crashed on assert(_jni_lock_count == count) failed: must be equal
Reviewed-by:

Threads which have been suspended weren't being visited by the logic
for maintaining the shared JNI critical count, resuling in incorrect
values.  It's a very rare problem that could only occur as a result of
JVMTI suspending a thread in the middle of a JNI critical operation
which should in general be rare.  It showed up in the nightlies with
regularity but I was unable to reproduce the original problem.  Adding
the new visited flag identified the issue immediately.  Tested with
tests from nightlies and the nsk JVMTI related tests.