[jdk17u-dev] RFR: 8345375: Improve debuggability of test/jdk/java/net/Socket/CloseAvailable.java

[Goetz Lindenmaier]

I backport this for parity with 17.0.15-oracle.

Patch applied clean, but I had to adapt the code to compile with Java 17.
Thread.ofPlatform().name("Close-Available-1") is not supported.

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Commit messages:
 - Backport 4b928167435bbf41dd00425c927da761751ca704

Changes: https://git.openjdk.org/jdk17u-dev/pull/3238/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=3238&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8345375
  Stats: 134 lines in 1 file changed: 43 ins; 12 del; 79 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/3238.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/3238/head:pull/3238

PR: https://git.openjdk.org/jdk17u-dev/pull/3238