RFR: Add JVMTI raw monitor lock/unlock mechanisms

[Jean Christophe Beyler]

Hi all,

I added the locks for the JVMTI raw monitors and added two tests, it is
failing the non racy ones due to the JVM locks not yet included but I think
that will resolve itself soon :)

I also moved the agent library to C++.

FWIW, we also need to clean up our tests that check for failing, right now
they pass because they generically just are checking for a TSAN race but
not specifically which one, which is a bit wrong / imprecise.

Webrev: http://cr.openjdk.java.net/~jcbeyler/jvmti/webrev.00/

Let me know what you think,
Jc