RFR: 8310238: [test bug] javax/swing/JTableHeader/6889007/bug6889007.java fails

[Phil Race]

This test fails *every* time when run as part of full set of jtreg tests and that is because it is sensitive to the initial mouse location,
and the previous test always sets it to within the location of this test's window.
The only reason it isn't problem listed is because on re-run - without that preceding test - it will pass.

More info in the bug report.

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

Commit messages:
 - 8310238

Changes: https://git.openjdk.org/jdk/pull/14527/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14527&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310238
  Stats: 24 lines in 1 file changed: 19 ins; 2 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/14527.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14527/head:pull/14527

PR: https://git.openjdk.org/jdk/pull/14527