RFR: 8344918: Unused private variables in SwingUtilities.java

[Phil Race]

Clean up of vars that are un-used.

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Commit messages:
 - 8344918

Changes: https://git.openjdk.org/jdk/pull/27804/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27804&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344918
  Stats: 4 lines in 1 file changed: 0 ins; 4 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/27804.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27804/head:pull/27804

PR: https://git.openjdk.org/jdk/pull/27804