cmd/compile: remove Node.Ntest, Node.Stkdelta

$ sizeof -p cmd/compile/internal/gc Node
Node 272
$

Change-Id: I3d9b67eebfc0be0a4b9768d3de3dc76300abd89c
Reviewed-on: https://go-review.googlesource.com/10521
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
diff --git a/src/cmd/compile/internal/gc/gsubr.go b/src/cmd/compile/internal/gc/gsubr.go
index fe3ee4e..93bd8a2 100644
--- a/src/cmd/compile/internal/gc/gsubr.go
+++ b/src/cmd/compile/internal/gc/gsubr.go
@@ -196,11 +196,11 @@
 		}
 
 		if p.From.Name == obj.NAME_AUTO && p.From.Node != nil {
-			p.From.Offset += ((p.From.Node).(*Node)).Stkdelta
+			p.From.Offset += stkdelta[p.From.Node.(*Node)]
 		}
 
 		if p.To.Name == obj.NAME_AUTO && p.To.Node != nil {
-			p.To.Offset += ((p.To.Node).(*Node)).Stkdelta
+			p.To.Offset += stkdelta[p.To.Node.(*Node)]
 		}
 
 		lp = &p.Link