RFR: JDK-8339962 : Open source AWT TextField tests - Set1

[Harshitha Onkar]

Following test are open-sourced.

1. 	test/jdk/java/awt/Label/ContainerValidateTest.java - Automated
2. 	test/jdk/java/awt/TextField/SetEchoCharTest.java - Automated
3. 	test/jdk/java/awt/TextField/SetEchoCharWordOpsTest.java - PassFailJFrame manual test

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Commit messages:
 - open source awt tests

Changes: https://git.openjdk.org/jdk/pull/21005/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21005&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339962
  Stats: 438 lines in 3 files changed: 438 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/21005.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21005/head:pull/21005

PR: https://git.openjdk.org/jdk/pull/21005