RFR: 8367376: call setUpdatePending(false) in a finally block

[Jeremy Wood]

Previously:

If DesktopProperty#updateAllUIs threw an exception, we would never reset the update-pending property to false. This means any subsequent call to `updateUI()` would not attempt to call `updateAllUIs()`

With this change:
Subsequent calls to DesktopProperty#updateUI() can still trigger at least one call to updateAllUIs().

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Commit messages:
 - 8367376: call setUpdatePending(false) in a finally block

Changes: https://git.openjdk.org/jdk/pull/27205/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27205&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367376
  Stats: 162 lines in 2 files changed: 159 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/27205.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27205/head:pull/27205

PR: https://git.openjdk.org/jdk/pull/27205