RFR: 8295013: OopStorage should derive from CHeapObjBase

[Kim Barrett]

Please review this change to OopStorage to derive from CHeapObjBase instead of
providing its own `operator new` and `operator delete`.

We also add OopStorage::create factory, so the MEMFLAGS used to allocate the
storage object will be the same as that passed to its constructor.  This
required a bunch of fairly mechanical updates to relevant gtests.

While I was there, also made OopStorage noncopyable.

Testing: mach5 tier1

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Commit messages:
 - OopStorage::create factory and uses CHeapObjBase

Changes: https://git.openjdk.org/jdk/pull/10622/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10622&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295013
  Stats: 192 lines in 5 files changed: 15 ins; 13 del; 164 mod
  Patch: https://git.openjdk.org/jdk/pull/10622.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10622/head:pull/10622

PR: https://git.openjdk.org/jdk/pull/10622