cmd/compile: use | in the last repetitive generic rules

cmd/compile: use | in the last repetitive generic rules

This change or-ifies the last low-hanging rules in generic. Again,
this is limited at short and repetitive rules, where the use or ors
does not impact readability.

Ran rulegen, no change in the actual compiler code.

Change-Id: I972b523bc08532f173a3645b47d6936b6e1218c8
Reviewed-on: https://go-review.googlesource.com/96335
Reviewed-by: Giovanni Bajo <rasky@develer.com>