[jdk17u-dev] RFR: 8343101: Rework BasicTest.testTemp test cases

[Goetz Lindenmaier]

I backport this for parity with 17.0.15-oracle.

This is based on the commit to 21. I needed to resolve again, though:
https://bugs.openjdk.org/browse/JDK-8291978: jpackage: allow to override primary l10n files on Windows is not in 17.

I include some of the edits of 8291978 in this change, as they nicely clean up the code.

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Commit messages:
 - Backport fe9284a8c523bc747e107836c85114864efab2a1

Changes: https://git.openjdk.org/jdk17u-dev/pull/3176/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=3176&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343101
  Stats: 101 lines in 3 files changed: 52 ins; 32 del; 17 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/3176.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/3176/head:pull/3176

PR: https://git.openjdk.org/jdk17u-dev/pull/3176