[jdk11u-dev] RFR: 8270116: Expand ButtonGroupLayoutTraversalTest.java to run in all LaFs, including Aqua on macOS

[Martin Doerr]

Clean backport of JDK-8270116.

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Commit messages:
 - Backport cb368802815c465f8eef7aa930d6cbb6540d0fa8

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/550/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=550&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8270116
  Stats: 114 lines in 1 file changed: 44 ins; 28 del; 42 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/550.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/550/head:pull/550

PR: https://git.openjdk.java.net/jdk11u-dev/pull/550