[jdk21u-dev] RFR: 8340007: Refactor KeyEvent/FunctionKeyTest.java

[Goetz Lindenmaier]

I backport this for parity with 21.0.6-oracle.

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Commit messages:
 - Backport 2faf8b8d582183275b1fdc92313a1c63c1753e80

Changes: https://git.openjdk.org/jdk21u-dev/pull/1029/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1029&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8340007
  Stats: 114 lines in 1 file changed: 62 ins; 15 del; 37 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1029.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1029/head:pull/1029

PR: https://git.openjdk.org/jdk21u-dev/pull/1029