RFR (S) 8251302: Create dedicated OopStorages for Management and Jvmti

[Coleen Phillimore]

These OopHandles are created and released during breakpoints and Thread 
stack walking operations.  They should have their own OopStorage so that 
GC can detect whether these things affect timing.

Tested with tier1-6.

open webrev at http://cr.openjdk.java.net/~coleenp/2020/8251302.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8251302

Thanks,
Coleen