[lworld] RFR: 8349110: [lworld] Intrinsics for Unsafe.get/putFlatValue [v3]

[Quan Anh Mai]

> Hi,
> 
> This PR implements intrinsics for `Unsafe::get/putFlatValue` and enables the corresponding tests in `TestIntrinsics`.
> 
> Please kindly review, thanks very much.

Quan Anh Mai has updated the pull request incrementally with one additional commit since the last revision:

  Revisit TODOs in TestIntrinsics

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

Changes:
  - all: https://git.openjdk.org/valhalla/pull/1482/files
  - new: https://git.openjdk.org/valhalla/pull/1482/files/0edc1de6..cf137ea9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1482&range=02
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1482&range=01-02

  Stats: 32 lines in 1 file changed: 0 ins; 31 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1482.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1482/head:pull/1482

PR: https://git.openjdk.org/valhalla/pull/1482