Fixed variable lifetime in loops

tests/programs/loop-lifetime.q

@@ -0,0 +1,17 @@
+main() {
+	n := 10
+	x := 1
+
+	loop {
+		if n == 0 {
+			return
+		}
+
+		f(x)
+		n -= 1
+	}
+}
+
+f(x) {
+	return x
+}

tests/programs/loop.q

@@ -0,0 +1,11 @@
+main() {
+	n := 10
+
+	loop {
+		if n == 0 {
+			return
+		}
+
+		n -= 1
+	}
+}

tests/programs_test.go

@@ -31,6 +31,8 @@ var programs = []struct {
 	{"branch-or", "", 0},
 	{"branch-both", "", 0},
 	{"jump-near", "", 0},
+	{"loop", "", 0},
+	{"loop-lifetime", "", 0},
 }
 
 func TestPrograms(t *testing.T) {