RFR: JDK-8297413: Remove easy warnings in javafx.graphics [v4]

[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 one additional commit since the last revision:

  Fix indentations and merge short lines

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Changes:
  - all: https://git.openjdk.org/jfx/pull/960/files
  - new: https://git.openjdk.org/jfx/pull/960/files/4cc73ecf..a81b9640

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=960&range=03
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=960&range=02-03

  Stats: 9 lines in 4 files changed: 1 ins; 2 del; 6 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