[dev.regabi] cmd/compile: remove Declare in makepartialcall

This is the only remaining late call to Declare. By changing it to use
Temp, we'll be able to move the legacy lexical scoping logic by moving
it to noder and iimport.

Passes toolstash -cmp.

Change-Id: Id7cf7a08e3138e50816f515fef3088785a10aaf4
Reviewed-on: https://go-review.googlesource.com/c/go/+/280513


Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>