[jdk17u-dev] RFR: 8320687: sun.jvmstat.monitor.MonitoredHost.getMonitoredHost() throws unexpected exceptions when invoked concurrently

[Paul Hohensee]

Backport for parity with Oracle 17.0.16. Clean except for copyright date in MonitoredHost.java, and replacement of try-with-resources in new test with try-catch because ExecutorService does not implement AutoClosable in 17u. New test passes, as well as the existing tests under test/jdk/sun/jvmstat/monitor.

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Commit messages:
 - Backport 81484d8c0520cf55ec58fc7b4c81880e69537674

Changes: https://git.openjdk.org/jdk17u-dev/pull/3593/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=3593&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8320687
  Stats: 105 lines in 2 files changed: 95 ins; 7 del; 3 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/3593.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/3593/head:pull/3593

PR: https://git.openjdk.org/jdk17u-dev/pull/3593