RFR: 8338153: java/awt/Checkbox/CheckboxCheckerScalingTest.java test failed on linux machine [v4]

[Tejesh R]

> Test failed intermittently on particular host. Though analysis pointed out to a test frame at left top on that host, I've updated the test for further stabilizing it. Two things done here:
> 1. Move the frame to center of the screen rather than left top.
> 2. Added tolerance checks for color comparison - this is based on analysis reports where the image didn't had exact black color which is supposed to be. So like other test cases, providing some tolerance for comparison.

Tejesh R has updated the pull request incrementally with one additional commit since the last revision:

  reduce tolerance value

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20723/files
  - new: https://git.openjdk.org/jdk/pull/20723/files/9a562914..0f28899d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20723&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20723&range=02-03

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/20723.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20723/head:pull/20723

PR: https://git.openjdk.org/jdk/pull/20723