cmd/compile: enforce strongly typed rules for ARM (5)
    
    From "absorb InvertFlags" until "constant folding in *shift ops"
    L666-L1011
    Toolstash-check is successful.
    
    Change-Id: Ieed7d4643dc3dc2b3649477e87aebd22c81d1322
    Reviewed-on: https://go-review.googlesource.com/c/go/+/234197
    Reviewed-by: Giovanni Bajo <rasky@develer.com>
    Reviewed-by: Keith Randall <khr@golang.org>
    Trust: Giovanni Bajo <rasky@develer.com>
    Run-TryBot: Giovanni Bajo <rasky@develer.com>
    TryBot-Result: Go Bot <gobot@golang.org>