Fix or delete idswitch

[tuchida]

ref. #863
Use ./gradlew spotlessApply.

before:

    private static final int
            Id_constructor = 1,

after:

    private static final int Id_constructor = 1,

In the case of after:, idswitch does not seem to find the Id_constructor.
https://github.com/mozilla/rhino/tree/0c05d30e134aed65b9c3536d8ac3764590840a35/toolsrc/org/mozilla/javascript/tools/idswitch

ref. #847
Since findPrototypeId is now a string switch, I don't see much advantage in using idswitch in the future, should I modify it?

[rbri]

For me my last hack was only to generate the new code. I think we can drop the idswitch tool and the generator hints from the code.

[rbri]

"Deleted code is debugged code." – Jeff Sickel