RFR: 8194946: Regression automated Test 'javax/swing/JFileChooser/6738668/bug6738668.java' fails

[Prasanta Sadhukhan]

Test was failing in CI system in nightly testing.
Saw it failed with HeadlessException in macos-x64 and mascos-aarch64 and with GTKL&F not supported in linux-x64 in headless CI system.
Made the test headful and test now passes in all platforms (link in JBS)

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Commit messages:
 - 8194946: Regression automated Test 'javax/swing/JFileChooser/6738668/bug6738668.java' fails

Changes: https://git.openjdk.java.net/jdk/pull/8202/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8202&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8194946
  Stats: 11 lines in 2 files changed: 9 ins; 1 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8202.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8202/head:pull/8202

PR: https://git.openjdk.java.net/jdk/pull/8202