Code Review request for bug fixes found by the Contended Locking project

[Daniel D. Daugherty]

Greetings,

I have been working on the Contended Locking project and there are some
bug fixes that I'd like to push into HSX-25 independently of the Contended
Locking project.

I'm using three different bug IDs to track these very distinct bug
fixes:

     6444286 Possible naked oop related to biased locking revocation
             safepoint in jni_exit()
     http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6444286
     https://jbs.oracle.com/bugs/browse/JDK-6444286

     8004902 correctness fixes motivated by contended locking work (6607129)
     http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8004902
     https://jbs.oracle.com/bugs/browse/JDK-8004902

     8004903 VMThread::execute() calls 
Thread::check_for_valid_safepoint_state()
             on concurrent VM ops
     http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8004903
     https://jbs.oracle.com/bugs/browse/JDK-8004903

Here is the URL for the webrev:

     http://cr.openjdk.java.net/~dcubed/cl_bug_fix_bucket-webrev/2/

These changes have been through two internal rounds of code review so I
think they are ready for wider review. The changes for 8004902 are very
tricky and there is long write-up attached to the 8004902 bug report that
explains the intricate details of the "triangular race". The changes for
6444286 and 8004903 are more straight forward.

These changes have been through JPRT build-and-test and have also been
tested with the vm.parallel_class_loading and vm.quick subsuites via
the Aurora ad-hoc testing mechanism.

The current set of reviewers is:

     acorn, dholmes, dice

As always, other reviewers are welcome. Comments, questions and
suggestions are also welcome.

Dan