[9] RFR(S): 8059846: InstanceKlass should use MutexLockerEx to acquire OsrList_lock

[Tobias Hartmann]

Hi,

please review this small code cleanup that replaces the explicit locking of 
OsrList_lock by a MutexLockerEx instantiation.

Bug: https://bugs.openjdk.java.net/browse/JDK-8059846
Webrev: http://cr.openjdk.java.net/~thartmann/8059846/webrev.00/

Thanks,
Tobias