[lworld] RFR: 8271710: [lworld] Unsafe compareAndSet/Exchange C2 intrinsics should support inline types

[Tobias Hartmann]

The C2 intrinsics for `Unsafe::compareAndSetReference` and `Unsafe::compareAndExchangeReference` need to handle scalarized inline type arguments by buffering. 

Best regards,
Tobias

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Commit messages:
 - 8271710: [lworld] Unsafe compareAndSet/Exchange C2 intrinsics should support inline types

Changes: https://git.openjdk.java.net/valhalla/pull/522/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=522&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8271710
  Stats: 232 lines in 2 files changed: 232 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/522.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/522/head:pull/522

PR: https://git.openjdk.java.net/valhalla/pull/522