math/big: fix copy-paste mistake in int_test.go

Change-Id: If986ed2cf94efba92763d00a3182047c05d6f805
Reviewed-on: https://go-review.googlesource.com/8133Reviewed-by: Minux Ma <minux@golang.org>

src/math/big/int_test.go

@@ -353,7 +353,7 @@ func checkBytes(b []byte) bool {
 }
 
 func TestBytes(t *testing.T) {
-	if err := quick.Check(checkSetBytes, nil); err != nil {
+	if err := quick.Check(checkBytes, nil); err != nil {
 		t.Error(err)
 	}
 }