RFR (S) 8014910 - deadlock between JVM/TI and compiler

[Ioi Lam]

Please review this fix:

http://cr.openjdk.java.net/~iklam/8014910/deadlock_jvmti_comp_001

Bug: deadlock between JVM/TI ClassPrepare event handler and CompilerThread

     https://bugs.openjdk.java.net/browse/JDK-8014910

Summary of fix:

     The deadlock was caused by this changeset:
        https://bugs.openjdk.java.net/browse/JDK-8008962
http://hg.openjdk.java.net/hsx/hsx25/hotspot/rev/c115fac239eb

     Because we use InstanceKlass::init_lock() for (1) class initialization,
     and (2) atomic modification of the class's constant pool, we could
     deadlock when

     thread A - holds class init lock and tries to grab compiler lock
     thread B - holds compiler lock and tries to lock constant pool

     The fix is to revert JDK-8008962 and use separate locks for (1) and 
(2).


Notes:
[1] Although the JDK-8008962 changeset modified instanceKlass.cpp
     and instanceKlass.hpp, the affected code (such as the original
     function InstanceKlass::fence_and_clear_init_lock) has been rendered
     unnecessary by other changes (8003421: NPG: Move oops out of
     InstanceKlass into mirror), so these two files do not need to be
     changed in this fix.


[2] I have filed a new bug to address the memory size issue in
     JDK-8008962:
        https://bugs.openjdk.java.net/browse/JDK-8026977
        Remove ConstantPool::lock

Tests:

     JPRT
     UTE (vm.runtime.testlist, vm.quick.testlist, 
vm.parallel_class_loading.testlist)
     JCK
     Test case in bug report.

Thanks
- Ioi