RFR: 8281033: Improve ImageCheckboxTest to test all available LaF

[Alexander Zuev]

Test modified to perform test on all available LaF's
During test development bug similar to JDK-8216358 was found in Nimbus and GTK+ LaFs
so exceptions were added and separate bugs were created to track these LaFs.

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Commit messages:
 - 8281033: Improve ImageCheckboxTest to test all available LaF

Changes: https://git.openjdk.java.net/jdk/pull/7439/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7439&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281033
  Stats: 49 lines in 1 file changed: 38 ins; 1 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7439.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7439/head:pull/7439

PR: https://git.openjdk.java.net/jdk/pull/7439