Added more tests

tests/programs/reassign.q

@@ -1,6 +1,6 @@
 main() {
-	x := 1
-	y := x + 1
-	x = 2
-	assert y == 2
+	a := 1
+	b := a + 1
+	a = 2
+	assert b == 2
 }

tests/programs/variables.q

@@ -0,0 +1,15 @@
+main() {
+	a := 1
+	b := 2
+	c := 3
+	d := 4
+	e := 5
+	f := 6
+	g := 7
+	h := 8
+
+	assert a != b
+	assert c != d
+	assert e != f
+	assert g != h
+}