Added nested calls test

tests/programs/multi-calls.q

@@ -1,7 +0,0 @@
-main() {
-	syscall(60, f(1) + f(2) + f(3))
-}
-
-f(x) {
-	return x + 1
-}

tests/programs/nested-calls.q

@@ -0,0 +1,11 @@
+main() {
+	exit(f(f(f(1))))
+}
+
+exit(code) {
+	syscall(60, code)
+}
+
+f(x) {
+	return x + 1
+}

tests/programs_test.go

@@ -16,10 +16,10 @@ var programs = []struct {
 	ExpectedExitCode int
 }{
 	{"empty.q", "", 0},
-	{"multi-calls.q", "", 9},
 	{"precedence.q", "", 10},
-	{"register-overlap.q", "", 9},
 	{"square-sum.q", "", 25},
+	{"chained-calls.q", "", 9},
+	{"nested-calls.q", "", 4},
 }
 
 func TestPrograms(t *testing.T) {