RFR: 8315965: Open source various AWT applet tests

[Alexander Zvegintsev]

Open sourcing few applet tests:

java/awt/ScrollPane/ScrollPaneTest.java
java/awt/TextArea/Length.java
java/awt/Window/WindowOwner.java
java/awt/font/Rotate/RotateTest3.java

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Commit messages:
 - initial

Changes: https://git.openjdk.org/jdk/pull/15754/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15754&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315965
  Stats: 548 lines in 4 files changed: 548 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15754.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15754/head:pull/15754

PR: https://git.openjdk.org/jdk/pull/15754