[lworld] RFR: 8315935: [lworld] Apply flat renaming to C2 code

[Frederic Parain]

Same renaming as in JDK-8315412 applied to C2 code.

Tested with Mach5, tier1

Fred

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Commit messages:
 - Fixing typos
 - Merge remote-tracking branch 'upstream/lworld' into c2_renaming
 - Flat renaming in C2

Changes: https://git.openjdk.org/valhalla/pull/925/files
 Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=925&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315935
  Stats: 270 lines in 38 files changed: 1 ins; 0 del; 269 mod
  Patch: https://git.openjdk.org/valhalla/pull/925.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/925/head:pull/925

PR: https://git.openjdk.org/valhalla/pull/925