RFR: 8253224: Shenandoah: ShenandoahStrDedupQueue destructor calls virtual num_queues()

[Aleksey Shipilev]

Static analysis complains that `ShenandoahStrDedupQueue` destructor calls virtual `num_queues()`. We can just do the
`_nv` version to make this right.

Testing: hotspot_gc_shenandoah

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Commit messages:
 - 8253224: Shenandoah: ShenandoahStrDedupQueue destructor calls virtual num_queues()

Changes: https://git.openjdk.java.net/jdk/pull/202/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=202&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253224
  Stats: 4 lines in 2 files changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/202.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/202/head:pull/202

PR: https://git.openjdk.java.net/jdk/pull/202