RFR: 8254841: [macos] Enter or Exit events are shouldn't be displayed while resizing [v2]

[Alisen Chung]

> Added a resizing flag when the window is currently being resized to block mouseEntered and mouseExited events from being posted to that window.

Alisen Chung has updated the pull request incrementally with one additional commit since the last revision:

  added bug ID to test

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5497/files
  - new: https://git.openjdk.java.net/jdk/pull/5497/files/f7f910bb..f455df82

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5497&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5497&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5497.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5497/head:pull/5497

PR: https://git.openjdk.java.net/jdk/pull/5497