Make IR for array access

tests/expectations/array_element_assignment.txt

@@ -0,0 +1 @@
+5

tests/expectations/print_array_element.txt

@@ -0,0 +1,2 @@
+5
+7

tests/vm/array_element_assignment.elna

@@ -1,3 +1,6 @@
 proc main() {
   var a: array[1] of int;
+  a[0] := 5;
+
+  printi(a[0]);
 }

tests/vm/print_array_element.elna

@@ -0,0 +1,8 @@
+proc main() {
+  var a: array[2] of int;
+  a[0] := 5;
+  a[1] := 7;
+
+  printi(a[0]);
+  printi(a[1]);
+}