add test files

js/js.translator/testFiles/operatorOverloading/cases/unaryOnIntProperty2.kt

@@ -0,0 +1,15 @@
+package foo
+
+class MyInt(i : Int) {
+  var b = i
+    fun inc() : MyInt {
+      b++;
+      return this;
+    }
+}
+
+fun box() : Boolean {
+  var t = MyInt(0)
+  t++;
+  return (t.b == 1)
+}