[crac] RFR: Fix lock usage in ReferenceQueue

[Anton Kozlov]

On Thu, 7 Sep 2023 08:48:00 GMT, Radim Vansa <rvansa at openjdk.org> wrote:

> In JDK 17 the locking used monitors, but in JDK 21 this class uses ReentrantLock. The change was not reflected during merge of new methods.

LGTM, thanks!

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Marked as reviewed by akozlov (Lead).

PR Review: https://git.openjdk.org/crac/pull/110#pullrequestreview-1625195678