RFR: 8346828: javax/swing/JScrollBar/4865918/bug4865918.java still fails in CI [v2]

[Prasanta Sadhukhan]

> Test seems to still fail in CI in ubuntu22.04 intermittently even after [JDK-8346324](https://bugs.openjdk.org/browse/JDK-8346324). Made the test headless similar to javax/swing/JScrollBar/bug4842792.java.

Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:

  Remove import/var

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/22937/files
  - new: https://git.openjdk.org/jdk/pull/22937/files/d4025132..6804cfd5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22937&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22937&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/22937.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22937/head:pull/22937

PR: https://git.openjdk.org/jdk/pull/22937