walkcompare already called walkexpr on n.Left and n.Right, which in
turn calls anylit when appropriate.

Passes toolstash-check.

Change-Id: I6912ac5a42b977c04db9d85cb2e7295e275e083d
Reviewed-on: https://go-review.googlesource.com/c/go/+/197600
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>