RFR: 8185429: [macos] After the dialog is closed, there is no window become active [v2]

[Alisen Chung]

> Add a check for previous focused window on modal unblocking. If the owner of a closing dialog was the last focused window, then the owner of the dialog should regain focus.

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

  use == over .equals

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Changes:
  - all: https://git.openjdk.org/jdk/pull/19588/files
  - new: https://git.openjdk.org/jdk/pull/19588/files/ff754beb..310af4b6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19588&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19588&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/19588.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19588/head:pull/19588

PR: https://git.openjdk.org/jdk/pull/19588