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
+}