RFR: 8265348: Shenandoah: Use timed wait to sleep control thread

[Zhengyu Gu]

I would like to bring the patch with the same synopsis from Shenandoah repo [1] to mainline, it should help what I am working on. 

Test:
- [x] hotspot_gc_shenandoah 

[1] https://github.com/openjdk/shenandoah/pull/28

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Commit messages:
 - Merge branch 'master' into JDK-8265348-control-timed-wait
 - init

Changes: https://git.openjdk.java.net/jdk/pull/3547/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3547&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8265348
  Stats: 16 lines in 2 files changed: 15 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3547.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3547/head:pull/3547

PR: https://git.openjdk.java.net/jdk/pull/3547