RFR: 8328248: Convert javax/swing/JSlider/6587742/bug6587742.java applet test to main

[Abhishek Kumar]

Conversion of manual applet test to main based using PassFailJFrame manual framework

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Commit messages:
 - Applet test converted to main manual

Changes: https://git.openjdk.org/jdk/pull/18323/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18323&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8328248
  Stats: 332 lines in 3 files changed: 166 ins; 166 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18323.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18323/head:pull/18323

PR: https://git.openjdk.org/jdk/pull/18323