cmd/compile: switch to typed auxint for arm64 TBZ/TBNZ block

This CL changes the arm64 TBZ/TBNZ block from using Aux to using
a (typed) AuxInt. The corresponding rules have also been changed
to be typed.

Passes

  GOARCH=arm64 gotip build -toolexec 'toolstash -cmp' -a std

Change-Id: I98d0cd2a791948f1db13259c17fb1b9b2807a043
Reviewed-on: https://go-review.googlesource.com/c/go/+/230839


Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>