RFR 8082782: vm crash on StressRedefineWithoutBytecodeCorruption fails with assert(((Metadata*)obj)->is_,valid()) failed: obj is valid

[Coleen Phillimore]

Summary: Walk compile task for Method* to not deallocate, store methods 
in methodHandle while compile task is being created

I couldn't reproduce this or write a test with the exact timing needed 
to get this crash, but this is what the stack trace and code inspection 
tells me what happened.  Reran all redefinition and internal tonga 
'quick' tests on the change with no regression.

open webrev at http://cr.openjdk.java.net/~coleenp/8082782.01/
bug link https://bugs.openjdk.java.net/browse/JDK-8082782

Thanks,
Coleen