[jdk17u-dev] RFR: 8353685: Open some JComboBox bugs 4

[Goetz Lindenmaier]

I backport this test change as it also goes to 17.0.17-oracle.

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Commit messages:
 - Backport 0b2a2f38d0b0133a562a898836d7a1b2dbd73a5e

Changes: https://git.openjdk.org/jdk17u-dev/pull/3598/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=3598&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8353685
  Stats: 255 lines in 3 files changed: 255 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/3598.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/3598/head:pull/3598

PR: https://git.openjdk.org/jdk17u-dev/pull/3598