RFR: 8289605: Robot capture tests fail intermittently on Mac M1

[Andy Goryachev]

- moving mouse pointer to stage lower right corner in order to avoid interference with the Robot screen capture.

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Commit messages:
 - 8289605: region tests

Changes: https://git.openjdk.org/jfx/pull/854/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=854&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8289605
  Stats: 34 lines in 2 files changed: 23 ins; 1 del; 10 mod
  Patch: https://git.openjdk.org/jfx/pull/854.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/854/head:pull/854

PR: https://git.openjdk.org/jfx/pull/854