RFR: 8328560: java/awt/event/MouseEvent/ClickDuringKeypress/ClickDuringKeypress.java imports Applet

[Phil Race]

This seems to have been some previous not very complete conversion of a test from applet to main.
It even still had Applet imported and miscellaneous comments. I've cleaned it up.

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Commit messages:
 - 8328560

Changes: https://git.openjdk.org/jdk/pull/18386/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18386&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8328560
  Stats: 95 lines in 1 file changed: 13 ins; 33 del; 49 mod
  Patch: https://git.openjdk.org/jdk/pull/18386.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18386/head:pull/18386

PR: https://git.openjdk.org/jdk/pull/18386