Fixes a bug where a num-uses counter wasn't being updated because of C
operator && semantics.  The code was something like "if (A && --B) ..."
but we want --B to happen even when A is false.

Sorts the LiveIn and LiveOut lists by regnum so that the lists always
display the set of registers in a consistent/familiar order.

BUG= none
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/1152813003