[lworld] RFR: 8367792: [lworld] Remove the Unsafe remnants of old valhalla prototypes

[Chen Liang]

There are some remnants from previous iterations of value objects in Unsafe. We should aim to remove them for cleaner code in the future.

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

Commit messages:
 - Remove old unsafe value stuff

Changes: https://git.openjdk.org/valhalla/pull/1593/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1593&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367792
  Stats: 630 lines in 13 files changed: 0 ins; 589 del; 41 mod
  Patch: https://git.openjdk.org/valhalla/pull/1593.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1593/head:pull/1593

PR: https://git.openjdk.org/valhalla/pull/1593