RFR: JDK-8297413: Remove easy warnings in javafx.graphics [v3]

[John Hendrikx]

> - Remove unsupported/unnecessary SuppressWarning annotations
> - Remove reduntant type specifications (use diamond operator)
> - Remove unused or duplicate imports
> - Remove unnecessary casts (type is already correct type or can be autoboxed)
> - Remove unnecessary semi-colons (at end of class definitions, or just repeated ones)
> - Remove redundant super interfaces (interface that is already inherited)
> - Remove unused type parameters
> - Remove declared checked exceptions that are never thrown
> - Add missing `@Override` annotations

John Hendrikx has updated the pull request incrementally with two additional commits since the last revision:

 - Revert changes to gesture recognizers to be addressed in follow up bug
 - Fix incorrect cast removals

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Changes:
  - all: https://git.openjdk.org/jfx/pull/960/files
  - new: https://git.openjdk.org/jfx/pull/960/files/b033ed1c..4cc73ecf

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=960&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=960&range=01-02

  Stats: 21 lines in 10 files changed: 8 ins; 0 del; 13 mod
  Patch: https://git.openjdk.org/jfx/pull/960.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/960/head:pull/960

PR: https://git.openjdk.org/jfx/pull/960