<Swing Dev> RFR: 8233570: [TESTBUG] HTMLEditorKit test bug5043626.java is failing on macos

[Prasanta Sadhukhan]

Please review a test fix for an issue seen to be failing on mach5 systems due to timing issue, which is not reproducible locally.
Modified the test to use setAutoDelay(), delay() after frame is made visible and also moved the frame to centre of screen. Removed the dependancy of Util class and also finally dispose of the frame.
Mach5 job has been run for several iterations in all platforms. Link in JBS.

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Commit messages:
 - Fixed jcheck issue
 - 8233570: [TESTBUG] HTMLEditorKit test bug5043626.java is failing on macos

Changes: https://git.openjdk.java.net/jdk/pull/896/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=896&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8233570
  Stats: 39 lines in 2 files changed: 14 ins; 4 del; 21 mod
  Patch: https://git.openjdk.java.net/jdk/pull/896.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/896/head:pull/896

PR: https://git.openjdk.java.net/jdk/pull/896