cmd/compile: add generic rules to remove bool → int → bool roundtrips

cmd/compile: add generic rules to remove bool → int → bool roundtrips

Change-Id: I8b0a3b64c89fe167d304f901a5d38470f35400ab
Reviewed-on: https://go-review.googlesource.com/c/go/+/715200
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Jorropo <jorropo.pgm@gmail.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Keith Randall <khr@golang.org>