Summary: Use OopStorage for strong oops stored with memory and thread
sampling and dumping, and remove oops_do and GC calls.
These use OopStorageSet::vm_global() OopStorage for now. I'll change
the thread sampling oops to use a new OopStorage once the GC code is
changed to nicely allow additional oop storages. The memory pool oops
are never deleted once created, so they should stay in vm_global() oop
storage.
Tested with tiers 1-3 (tiers 4-6 with other changes) and
javax/management tests. I timed the tests to see if there was any
noticeable performance difference, and there was not.
open webrev at http://cr.openjdk.java.net/~coleenp/2020/8247878.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8247878
Thanks,
Coleen
