RFR: JDK-8282046: Create a regression test for CCC8000326

[Srinivas Mandalika]

Create a regression test for CCC8000326

Issue is identified by [JDK-8000326](https://bugs.openjdk.java.net/browse/JDK-8000326), which identifies that after focus moves into JMenuBar, whose focus traversal key is disabled by default, it never moves to other focusable component.
 
By default, pressing the Tab key does not transfer focus from a JMenuBar which is added to a container together with other Swing components, because the focusTraversalKeysEnabled property of JMenuBar is set to false. To resolve this, you should call the JMenuBar.setFocusTraversalKeysEnabled(true) method.
 
The test verifies focus traversal for the above described scenario.

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Commit messages:
 - JDK-8282046: Create a regression test for CCC8000326
 - JDK-8282046: Create a regression test for CCC8000326

Changes: https://git.openjdk.java.net/jdk/pull/7512/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7512&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8282046
  Stats: 107 lines in 1 file changed: 107 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7512.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7512/head:pull/7512

PR: https://git.openjdk.java.net/jdk/pull/7512