RFR 8229844: Remove attempt_rebias parameter from revoke_and_rebias()

[Patricio Chilano]

Hi all,

Please have a look at the following patch.

JBS: https://bugs.openjdk.java.net/browse/JDK-8229844
Webrev: http://cr.openjdk.java.net/~pchilanomate/8229844/v01/webrev/

The attempt_rebias parameter is only used by 
ObjectSynchronizer::fast_enter() after we failed to acquire the lock in 
interpreter/compiler code. But even in that case the rebiasing will only 
work for the bulk rebiasing case, i.e. after a safepoint occurs, so not 
only this is not the common case but also there is nothing really fast 
about it. We can remove it without any real performance penalty and 
simplify the code. Also this allows to merge the fast_enter() and 
slow_enter() into a common enter() and remove biased locking knowledge 
in other parts of the code. Tested with tiers1-6 on Linux, Windows, OSX 
and Solaris.

Thanks!
Patricio