[lworld] RFR: Remove ensure_objArray and copying code and write a test

[Coleen Phillimore]

This is the diff for removing copy_flatArray_to_objArray and ensure_objArray.  This is relative to lworld but should apply cleanly to your PR Fred.  I tested it against the tier1 tests in the lworld repo (in progress).

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Commit messages:
 - Remove ensure_objArray and copying code and write a test.

Changes: https://git.openjdk.org/valhalla/pull/1507/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1507&range=00
  Stats: 118 lines in 4 files changed: 95 ins; 21 del; 2 mod
  Patch: https://git.openjdk.org/valhalla/pull/1507.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1507/head:pull/1507

PR: https://git.openjdk.org/valhalla/pull/1507