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

[Roberto Castañeda Lozano]

On Wed, 7 Sep 2022 11:45:45 GMT, Tobias Holenstein <tholenstein at openjdk.org> wrote:

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

This changeset goes beyond trivial cleanups (removing dead code, trailing whitespace, legacy functionality, etc.), and it would help if you could summarize (and motivate if necessary) the main changes in it.

I found that switching among opened graphs from different groups does not update anymore the highlighted graphs in the Outline window, nor the content of the Bytecode and Control Flow windows. Maybe an effect of splitting #10164?

A few more comments:
- I would also prefer to leave the `toString()` methods in, for ease of debugging.
- Why are some tests in `InputGraphTest.java` removed? Were they not run before?
- I agree with enforcing alphabetic order of imports, but I would personally prefer to import explicitly all individual classes rather than using wildcards (matter of taste though, I do not think we have any style guidelines for tools like IGV).
- Please update the copyright headers, at least for files with non-trivial changes.

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Changes requested by rcastanedalo (Reviewer).

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