[jdk17u-dev] RFR: 8273921: Refactor NSK/JDI tests to create thread using factory

[Goetz Lindenmaier]

I backport this to keep the tests up to date.
Simplifies follow up backports of actual fixes.

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Commit messages:
 - Backport a72c8aa6ad58bad57ddbd65139bcb88b6d8aa5db

Changes: https://git.openjdk.org/jdk17u-dev/pull/1867/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1867&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8273921
  Stats: 1943 lines in 205 files changed: 108 ins; 576 del; 1259 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1867.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1867/head:pull/1867

PR: https://git.openjdk.org/jdk17u-dev/pull/1867