[lworld] RFR: 8373374: [lworld] Remove Unsafe.get/putValue [v2]

[Chen Liang]

> Remove the old Unsafe getValue and putValue, which had some performance difficulties because they are megamorphic depending on the exact layout.

Chen Liang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'lworld' of https://github.com/openjdk/valhalla into cleanup/unsafe-value
 - Remove get/putVal

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

Changes:
  - all: https://git.openjdk.org/valhalla/pull/1782/files
  - new: https://git.openjdk.org/valhalla/pull/1782/files/708675bc..860e902f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1782&range=01
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1782&range=00-01

  Stats: 28844 lines in 505 files changed: 18426 ins; 7131 del; 3287 mod
  Patch: https://git.openjdk.org/valhalla/pull/1782.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1782/head:pull/1782

PR: https://git.openjdk.org/valhalla/pull/1782