RFR: 8367989: Remove InstanceKlass::allocate_objArray [v3]

[Coleen Phillimore]

> This change removes InstanceKlass::allocate_objArray and has its caller call ObjArrayKlass::allocate_instance directly from oopFactory, like the other array allocations do.  See CR for more information why we should have this change.  I also removed element_klass_addr() and moved element_klass_offset() to be in a more logical place near element_klass() functions.  This upstreams a tiny valhalla diff.
> Tested with tier1-4.

Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:

  Use virtual function rather than if statement, still need one cast though.

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/27372/files
  - new: https://git.openjdk.org/jdk/pull/27372/files/f4f1d289..cfa036b4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27372&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27372&range=01-02

  Stats: 6 lines in 1 file changed: 0 ins; 5 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27372.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27372/head:pull/27372

PR: https://git.openjdk.org/jdk/pull/27372