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. ------------- 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
