[master] RFR: Remove a couple LIGHTWEIGHT things from the legacy/monitor version of FastHashCode

[Coleen Phillimore]

This branches off for lightweight mode, but there were a couple of lightweight cases left over.
Tested locally hotspot:tier1 with default and with -XX:LockingMode=1.

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Commit messages:
 - Remove a couple LIGHTWEIGHT things from the legacy/monitor version of FastHashCode

Changes: https://git.openjdk.org/lilliput/pull/179/files
  Webrev: https://webrevs.openjdk.org/?repo=lilliput&pr=179&range=00
  Stats: 5 lines in 1 file changed: 0 ins; 3 del; 2 mod
  Patch: https://git.openjdk.org/lilliput/pull/179.diff
  Fetch: git fetch https://git.openjdk.org/lilliput.git pull/179/head:pull/179

PR: https://git.openjdk.org/lilliput/pull/179