[lworld] RFR: 8293542: [lworld] Merge InlineTypeNode and InlineTypePtrNode in C2

[Tobias Hartmann]

This is a large refactoring, removing the need to have both an `InlineTypeNode` as well as an `InlineTypePtrNode` in C2, significantly simplifying the IR. The change also includes several bug fixes that could not be easily extracted into an independent change.

More cleanups will follow with [JDK-8293800](https://bugs.openjdk.org/browse/JDK-8293800).

Thanks,
Tobias

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

Commit messages:
 - Minor fix for flat arrays
 - Merge branch 'lworld' into JDK-8293542
 - Merge branch 'lworld' into JDK-8293542
 - More fixes
 - More cleanups
 - 8293542: [lworld] Merge InlineTypeNode and InlineTypePtrNode in C2

Changes: https://git.openjdk.org/valhalla/pull/780/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=780&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8293542
  Stats: 810 lines in 33 files changed: 177 ins; 348 del; 285 mod
  Patch: https://git.openjdk.org/valhalla/pull/780.diff
  Fetch: git fetch https://git.openjdk.org/valhalla pull/780/head:pull/780

PR: https://git.openjdk.org/valhalla/pull/780