RFR(S) 8187040: ThreadCritical crashes on Solaris if used between os::init and os::init_2

[Mikael Gerdin]

Hi,

Please review this small fix to ThreadCritical.
When working on a piece of code which allocates memory early on I 
noticed that it crashed if I enabled NMT.
The reason is that NMT uses ThreadCritical and os::Solaris sets the 
ThreadCritical::_initialized flag before it actually sets up the 
function pointers the flag is supposed to guard.
os::Solaris::_mutex_lock is not initialized until the init_2 phase 
(after command line flag parsing).

My suggested fix is to replace the current short-circuit of 
ThreadCritical with a flag set when the Solaris mutex code is 
initialized and thereby getting rid of the initialize function on all 
platforms.
Additionally, ThreadCritical::release is unreachable code and from my 
research has never actually been called, we might as well get rid of it.

Webrev: http://cr.openjdk.java.net/~mgerdin/8187040/webrev.0/
Bug: https://bugs.openjdk.java.net/browse/JDK-8187040
Testing: JPRT

Thanks
/Mikael