[jdk21u-dev] RFR: 8340210: Add positionTestUI() to PassFailJFrame.Builder

[Goetz Lindenmaier]

I backport this for parity with 21.0.6-oracle.

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Commit messages:
 - Backport f0ae90f30c346544e87217ef1832d6a350fe1985

Changes: https://git.openjdk.org/jdk21u-dev/pull/1075/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1075&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8340210
  Stats: 23 lines in 1 file changed: 23 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1075.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1075/head:pull/1075

PR: https://git.openjdk.org/jdk21u-dev/pull/1075