cmd/internal/gc, cmd/internal/obj: clean up string returns
An artifact of the c2go translation was
a handful of instances of code like:
var s string
s += "foo"
return s
This CL converts those to simply 'return "foo"'.
The conversion was done mechanically with the
quick-and-dirty cleanup script at
https://gist.github.com/josharian/
1fa4408044c163983e62.
I then manually moved a couple of comments in fmt.go.
toolstash -cmp thinks that there are no functional changes.
Change-Id: Ic0ebdd10f0fb8de0360a1041ce5cd10ae1168be9
Reviewed-on: https://go-review.googlesource.com/6265
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>