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

[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

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Commit messages:
 - Removed debug code
 - 8267846: [lworld] JIT support for the L/Q model (step 1)

Changes: https://git.openjdk.java.net/valhalla/pull/431/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=431&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267846
  Stats: 343 lines in 38 files changed: 142 ins; 47 del; 154 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