add test files

js/js.translator/testFiles/expression/function/cases/adderClosure.kt

@@ -0,0 +1,9 @@
+package foo
+
+fun box() : Boolean {
+  var sum = 0
+  val adder = {(a: Int) -> sum += a }
+  adder(3)
+  adder(2)
+  return sum == 5
+}