[dev.unified] cmd/compile/internal/noder: prefer *At functions
[dev.unified] cmd/compile/internal/noder: prefer *At functions

Unified IR tries to avoid depending on base.Pos, so we should prefer
explicit position arguments wherever possible.

Change-Id: I7163b1b8c5244fe7c2a7989e6a3f459a21a23e81
Reviewed-on: https://go-review.googlesource.com/c/go/+/418096
Reviewed-by: Cuong Manh Le <54b4457f1dff6823379654eb5867596497ba782f@gmail.com>
Run-TryBot: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>
Reviewed-by: David Chase <ae171625adc8645b8b79b7e405a6da5aba5341e0@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go,golang/go