RFR: 8281569: Create tests for Frame.setMinimumSize() method

[Srinivas Mandalika]

Create tests for setMinimumSize functionality
Create a test which verifies that on increasing the Frame's minimumSize, it gets reflected in the subsequent getSize call
Create a test which verifies that on frame resizes back to minimumSize on calling pack.

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Commit messages:
 - 8281569: Create tests for Frame.setMinimumSize() method
 - 8281569: Create tests for Frame.setMinimumSize() method

Changes: https://git.openjdk.java.net/jdk/pull/7444/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7444&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281569
  Stats: 180 lines in 2 files changed: 180 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7444.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7444/head:pull/7444

PR: https://git.openjdk.java.net/jdk/pull/7444