cmd/compile: remove useless declaration of llit

Accidentally added in https://golang.org/cl/20242.

This is in preparation for transformation by an automated tool.

Passes toolstash -cmp.

Update #14473.

Change-Id: I28c637d220df3ccaa8e368bfbea7282a6e66662e
Reviewed-on: https://go-review.googlesource.com/20402
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/compile/internal/gc/typecheck.go

@@ -3338,9 +3338,8 @@ func typecheckas2(n *Node) {
 	var r *Node
 	if cl == cr {
 		// easy
-		llit := nodeSeqIterate(n.List)
 		lrit := nodeSeqIterate(n.Rlist)
-		for llit = nodeSeqIterate(n.List); !llit.Done(); llit.Next() {
+		for llit := nodeSeqIterate(n.List); !llit.Done(); llit.Next() {
 			if llit.N().Type != nil && lrit.N().Type != nil {
 				*lrit.P() = assignconv(lrit.N(), llit.N().Type, "assignment")
 			}