[9] RFR(XXS): 8043158: Crash in CodeSweeperSweepNoFlushTest in CompileQueue::free_all()

[Albert]

Hi,

could I get reviews for this small patch?

Bug:
https://bugs.openjdk.java.net/browse/JDK-8043158

Problem:
In CompileQueue::free_all() we call notify() on a compile task although 
we do not own the
lock of the compile task object.

Solution:
Acquire lock before calling notify()

Testing:
Failing test case

Webrev:
http://cr.openjdk.java.net/~anoll/8043158/webrev.00/

Many thanks in advance,
Albert