[lworld] RFR: 8249869: [lworld] Remove LW2 specific code from the JIT [v4]

[Tobias Hartmann]

> The concept of flattenable fields needs some cleanup (inline types are always flattenable/null-free). We can remove the
> side-channel introduced by JDK-8212190. See JDK-8247357 for details.

Tobias Hartmann has updated the pull request incrementally with one additional commit since the last revision:

  Renaming ValueArrayFlatten -> UseFlatArray

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

Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/116/files
  - new: https://git.openjdk.java.net/valhalla/pull/116/files/7564397b..3edaa382

Webrevs:
 - full: https://webrevs.openjdk.java.net/valhalla/116/webrev.03
 - incr: https://webrevs.openjdk.java.net/valhalla/116/webrev.02-03

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/116.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/116/head:pull/116

PR: https://git.openjdk.java.net/valhalla/pull/116