Adds test infrastructure for JS optimizer. Adds simple tests

js/js.translator/testData/js-optimizer/temporary-variable/assignment.optimized.js

@@ -0,0 +1,10 @@
+function test(a, b, c) {
+    return a + b + c;
+}
+
+function box() {
+    var result = test(2, 3, 4);
+    if (result != 9) return "fail: " + result;
+
+    return "OK"
+}