pass: allow consecutive labels (#123)

Fixes #122

tests/fixedbugs/issue122/issue122_test.go

@@ -0,0 +1,16 @@
+package issue122
+
+import (
+	"testing"
+)
+
+//go:generate go run asm.go -out issue122.s -stubs stub.go
+
+func TestTriangle(t *testing.T) {
+	expect := func(n uint64) uint64 { return n * (n + 1) / 2 }
+	for n := uint64(1); n < 42; n++ {
+		if got := Triangle(n); expect(n) != got {
+			t.Fatalf("Triangle(%v) = %v; expect %v", n, got, expect(n))
+		}
+	}
+}