RFR: 8289396: Fix warnings: Null pointer access: The variable instance can only be null at this location

[Andy Goryachev]

- removed meaningless test case

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Commit messages:
 - 8289396: removed meaningless test case

Changes: https://git.openjdk.org/jfx/pull/813/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=813&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8289396
  Stats: 12 lines in 1 file changed: 0 ins; 11 del; 1 mod
  Patch: https://git.openjdk.org/jfx/pull/813.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/813/head:pull/813

PR: https://git.openjdk.org/jfx/pull/813