JS: move more test to box tests

js/js.translator/testData/box/operatorOverloading/overloadedCallOnProperty.kt

@@ -0,0 +1,21 @@
+package foo
+
+var a = MyInt()
+
+class MyInt() {
+    var b = 0
+
+    operator fun inc(): MyInt {
+        val res = MyInt();
+        res.b = b;
+        res.b++;
+        return res;
+    }
+}
+
+
+fun box(): String {
+    a++;
+    a++;
+    return if (a.b == 2) "OK" else "fail"
+}