RFR: JDK-8290011: IGV: Remove dead code and cleanup

[Tobias Holenstein]

Remove dead code from the IGV code base. There are many unused or redundant functions in the code

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Commit messages:
 - sort all imports
 - removed unused imports
 - remove various unused variables and methods
 - remove unused getRightWidget() and getLeftWidget()
 - remove comment
 - added missing asynchronous()
 - Fix Netbeans position warning
 - remove broken HideDuplicatesAction
 - remove InputGraph from Diagram
 - refactor diagramChanged()
 - ... and 21 more: https://git.openjdk.org/jdk/compare/512fee1d...e5201fd4

Changes: https://git.openjdk.org/jdk/pull/10197/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10197&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290011
  Stats: 3480 lines in 97 files changed: 199 ins; 3000 del; 281 mod
  Patch: https://git.openjdk.org/jdk/pull/10197.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10197/head:pull/10197

PR: https://git.openjdk.org/jdk/pull/10197