Implemented negation

tests/programs/negation.q

@@ -0,0 +1,7 @@
+main() {
+	syscall(60, f(-32))
+}
+
+f(x) {
+	return -x
+}

tests/programs_test.go

@@ -43,6 +43,7 @@ var programs = []struct {
 	{"loop-lifetime", "", "", 0},
 	{"assert", "", "", 1},
 	{"negative", "", "", 32},
+	{"negation", "", "", 32},
 }
 
 func TestPrograms(t *testing.T) {