RFR: 8234303: [TEST_BUG] Correct ignore tag in graphics unit tests

[Ambarish Rapte]

This is a simple fix to correct all the ignored tag in graphics unit tests.

Corrections are:
1. Each ignored test must be associated with a bug. There are new bugs reported for all the tests which are missing a bug.
2. Replace @org.junit.Ignore with @Ignore.
3. Remove unused import statement. 

Test count is same before and after this change on all three platforms.
tests: 22982,  failures: 0,  ignored: 273

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Commits:
 - 90b132f5: 8234303: [TEST_BUG] Correct ignore tag in graphics unit tests

Changes: https://git.openjdk.java.net/jfx/pull/44/files
 Webrev: https://webrevs.openjdk.java.net/jfx/44/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8234303
  Stats: 114 lines in 14 files changed: 15 ins; 4 del; 95 mod
  Patch: https://git.openjdk.java.net/jfx/pull/44.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/44/head:pull/44

PR: https://git.openjdk.java.net/jfx/pull/44