RFR: 8285698: Create a test to check the focus stealing of JPopupMenu from JComboBox

Wed Apr 27 11:39:14 UTC 2022

This test verifies that showing a JPopupMenu shouldn't steal the focus out of current focused component..
This fix moves an unstable closed test to open but updated to be more comprehensive in testing multiple Look and Feels and with some stabilisation improvements. The closed test had some dependencies with some proprietary libraries which are all removed here.

Testing:
Tested using mach5 10 times per platform and got all Pass.

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Commit messages:
 - 8285698: Create a test to check the focus stealing of JPopupMenu from JComboBox

Changes: https://git.openjdk.java.net/jdk/pull/8426/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8426&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8285698
  Stats: 183 lines in 1 file changed: 183 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8426.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8426/head:pull/8426

PR: https://git.openjdk.java.net/jdk/pull/8426