RFR: 8279297: Remove Shape::setMode method

[Andy Goryachev]

- removed unused method

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Commit messages:
 - 8279297: removed unused Shape.setMode method

Changes: https://git.openjdk.org/jfx/pull/814/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=814&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8279297
  Stats: 16 lines in 2 files changed: 0 ins; 14 del; 2 mod
  Patch: https://git.openjdk.org/jfx/pull/814.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/814/head:pull/814

PR: https://git.openjdk.org/jfx/pull/814