RFR: 8294254: [macOS] javax/swing/plaf/aqua/CustomComboBoxFocusTest.java failure [v3]

[Damon Nguyen]

> The previous change to AquaComboBoxUI had 1 pixel of overlap between the text field and the combo button. This caused a few pixels to darken sometimes when an editable combobox is displayed. Since this test passes sometimes and fails some other times, it was not initially detected.
> 
> Since these few darkening pixels occur due to the change in AquaComboBoxUI, no reasonable change to the test could really be made, and the change would need to be to the class for the combobox. This fix was tested with a high count repeat and no failures occurred for various macOS systems.
> 
> Also removing the test from the problem list.

Damon Nguyen has updated the pull request incrementally with two additional commits since the last revision:

 - Merge branch '8294254/overlapFixEditableCombobox' of github.com:DamonGuy/jdk into 8294254/overlapFixEditableCombobox
 - Set uiscale

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/10626/files
  - new: https://git.openjdk.org/jdk/pull/10626/files/6ee1f92f..8c0e0d8e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10626&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10626&range=01-02

  Stats: 5 lines in 1 file changed: 2 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/10626.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10626/head:pull/10626

PR: https://git.openjdk.org/jdk/pull/10626