two tests crash intermittently during java.lang.Thread.exit on Windows-64

In the 2012.08.06 RT_Baseline nightly, the following two tests
crashed during a ava.lang.Thread.exit() in the native part of
java.lang.System.arraycopy():

    nsk/jdi/ThreadReference/forceEarlyReturn/forceEarlyReturn015
    nsk/jdi/VirtualMachine/redefineClasses/redefineclasses034

Here is a snippet from the hs_err_pid file:

# A fatal error has been detected by the Java Runtime Environment:
#
# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0000000071dbd472, pid=5044, tid=14264
#
# JRE version: Java(TM) SE Runtime Environment (7.0_06-b22)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (24.0-b20-internal-201208061641.ddaugher.merge_main_to_rt_b-fastdebug mixed mode windows-amd64 compressed oops)
# Problematic frame:
# V [jvm.dll+0xd472]
#
# Core dump written. Default location: C:\local\85269.JAVASE.NIGHTLY.VM.RT_Baseline.2012-08-06.windows-amd64_vm__server_mixed_nsk.quick-jdi.testlist.runTests\results\ResultDir\forceEarlyReturn015\hs_err_pid5044.mdmp
#
# If you would like to submit a bug report, please visit:
# http://bugreport.sun.com/bugreport/crash.jsp
#

<snip>

Stack: [0x00000000021e0000,0x00000000022e0000], sp=0x00000000022df510, free space=1021k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [jvm.dll+0xd472]Warning: Warning: no map file found for C:/local/common/jdk/baseline/windows-amd64/jre/bin/server/jvm.dll!



[error occurred during error reporting (printing native stack), id 0xc0000005]

Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
J java.lang.System.arraycopy(Ljava/lang/Object;ILjava/lang/Object;II)V
j java.lang.ThreadGroup.remove(Ljava/lang/Thread;)V+59
j java.lang.ThreadGroup.threadTerminated(Ljava/lang/Thread;)V+6
j java.lang.Thread.exit()V+12
v ~StubRoutines::call_stub