RFR: fix for casLockState intrinsic

[Dean Long]

Read of to/from args needs to be 32-bit.  Also simplified masking logic.

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Commit messages:
 - fix for casLockState intrinsic

Changes: https://git.openjdk.org/loom/pull/204/files
 Webrev: https://webrevs.openjdk.org/?repo=loom&pr=204&range=00
  Stats: 9 lines in 1 file changed: 1 ins; 6 del; 2 mod
  Patch: https://git.openjdk.org/loom/pull/204.diff
  Fetch: git fetch https://git.openjdk.org/loom.git pull/204/head:pull/204

PR: https://git.openjdk.org/loom/pull/204