RFR: 8341535: sun/awt/font/TestDevTransform.java fails with RuntimeException: Different rendering

[Phil Race]

Add some tolerance to this test before failing and make it dump the images if it does fail.

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Commit messages:
 - 8341535

Changes: https://git.openjdk.org/jdk/pull/21363/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21363&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8341535
  Stats: 25 lines in 1 file changed: 19 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/21363.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21363/head:pull/21363

PR: https://git.openjdk.org/jdk/pull/21363