RFR: 8281296: Create a regression test for JDK-4515999

[Manukumar V S]

Create a regression test for [JDK-4515999](https://bugs.openjdk.java.net/browse/JDK-4515999)
Create a test which checks whether incrementing dates via the keyboard (up/down) gives the same results as when using mouse press on the arrow buttons in a JSpinner.

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Commit messages:
 - 8281296: Create a regression test for JDK-4515999

Changes: https://git.openjdk.java.net/jdk/pull/7363/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7363&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281296
  Stats: 169 lines in 1 file changed: 169 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7363.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7363/head:pull/7363

PR: https://git.openjdk.java.net/jdk/pull/7363