RFR: JDK-8297412: Remove easy warnings in javafx.media, javafx.swing, javafx.swing and javafx.web

[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

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Commit messages:
 - Remove unused import
 - Remove redundant type specifications
 - Remove unnecessary casts
 - Remove unnecessary semi-colons
 - Remove unused declared exceptions and add override annotations
 - Remove unused imports in fxml, swing, swt and web

Changes: https://git.openjdk.org/jfx/pull/958/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=958&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8297412
  Stats: 1566 lines in 235 files changed: 1130 ins; 98 del; 338 mod
  Patch: https://git.openjdk.org/jfx/pull/958.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/958/head:pull/958

PR: https://git.openjdk.org/jfx/pull/958