RFR: JDK-8318736: com/sun/jdi/JdwpOnThrowTest.java failed with "transport error 202: bind failed: Address already in use"

[Johannes Bechberger]

Fix race condition in debugger port selection, introduced with [JDK-8317920](https://bugs.openjdk.org/browse/JDK-8317920).

Tested on my Mac M1, but it doesn't contain platform-dependent code.

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Commit messages:
 - Fix Debuggee creation

Changes: https://git.openjdk.org/jdk/pull/16358/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16358&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318736
  Stats: 46 lines in 3 files changed: 17 ins; 23 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/16358.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16358/head:pull/16358

PR: https://git.openjdk.org/jdk/pull/16358