[jdk11u-dev] RFR: 8316947: Write a test to check textArea triggers MouseEntered/MouseExited events properly

[Andrew Lu]

I backport this for parity with 11.0.23-oracle.

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Commit messages:
 - Backport 00ef9f9c322dde236256953272d6906f6151635d

Changes: https://git.openjdk.org/jdk11u-dev/pull/2474/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2474&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316947
  Stats: 132 lines in 1 file changed: 132 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2474.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2474/head:pull/2474

PR: https://git.openjdk.org/jdk11u-dev/pull/2474