No behavior change; just inverting the loop ordering so the
per-parameter behavior is a bit clearer.

Passes toolstash-check.

Updates #33981.

Change-Id: I9bfcd7d0a4aff65a27ced157767ca2ba8038319a
Reviewed-on: https://go-review.googlesource.com/c/go/+/193177
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>