RFR: 8267846: [lworld] JIT support for the L/Q model (step 1) [v2]

[Tobias Hartmann]

> After https://github.com/openjdk/valhalla/pull/409 and https://github.com/openjdk/valhalla/pull/414 have been integrated, we need to fix the JIT code as well. This mostly means re-applying the old changes from https://github.com/openjdk/valhalla/commit/22dd0da1 and https://github.com/openjdk/valhalla/commit/e895128f and adjust them to the current implementation.
> 
> All compiler tests now pass except for `TestNullableInlineTypes`, `TestNullableArrays` and `TestIntrinsics` which need reflection support. The corresponding C2 intrinsics are still broken. I'll fix them with [JDK-8267932](https://bugs.openjdk.java.net/browse/JDK-8267932) once reflection support is available.
> 
> Thanks,
> Tobias

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

  constantTag::internal_name() fix

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

Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/431/files
  - new: https://git.openjdk.java.net/valhalla/pull/431/files/580cb505..eb8e2b09

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=valhalla&pr=431&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=valhalla&pr=431&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/431.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/431/head:pull/431

PR: https://git.openjdk.java.net/valhalla/pull/431