RFR (M): Various cleanups: (un)signed math, method names, leftover code, etc

[Aleksey Shipilev]

Hi,

I have managed to open Hotspot in CLion, and it barraged me with
warnings I could not resist to fix. These include some (un)signed math
problems, inconsistent method names, leftover code, etc.

See:
  http://cr.openjdk.java.net/~shade/shenandoah/cleanups-1/webrev.01/

This is not entirely complete, but fixes some blatantly obvious things.
Ok to go?

Thanks,
-Aleksey