fix(transpile): fix usage of int and references to assert module

modules/angular2/src/facade/collection.es6

@@ -166,8 +166,8 @@ export class ListWrapper {
   static isEmpty(list) {
     return list.length == 0;
   }
-  static fill(list:List, value, start:int = 0, end:int = undefined) {
-    list.fill(value, start, end);
+  static fill(list:List, value, start:int = 0, end:int = null) {
+    list.fill(value, start, end === null ? undefined: end);
   }
   static equals(a:List, b:List):boolean {
     if(a.length != b.length) return false;

modules/angular2/src/facade/lang.es6

@@ -1,12 +1,24 @@
-import {assert} from 'rtts_assert/rtts_assert';
 export {proxy} from 'rtts_assert/rtts_assert';
 
 export var Type = Function;
 export var Math = window.Math;
 
+var assertionsEnabled_ = typeof assert !== 'undefined';
+
+var int;
 // global assert support, as Dart has it...
 // TODO: `assert` calls need to be removed in production code!
-window.assert = assert;
+if (assertionsEnabled_) {
+  window.assert = assert;
+  // `int` is not a valid JS type
+  int = assert.define('int', function(value) {
+    return typeof value === 'number' && value%1 === 0;
+  });
+} else {
+  int = {};
+  window.assert = function() {};
+}
+export {int};
 
 export class FIELD {
   constructor(definition) {
@@ -71,8 +83,8 @@ export class StringWrapper {
     return s.startsWith(start);
   }
 
-  static substring(s:string, start:int, end:int = undefined) {
-    return s.substring(start, end);
+  static substring(s:string, start:int, end:int = null) {
+    return s.substring(start, end === null ? undefined: end);
   }
 
   static replaceAllMapped(s:string, from:RegExp, cb:Function): string {
@@ -157,18 +169,18 @@ export class NumberWrapper {
   }
 }
 
-export function int() {};
-int.assert = function(value) {
-  return value == null || typeof value == 'number' && value === Math.floor(value);
+var RegExp;
+if (assertionsEnabled_) {
+  RegExp = assert.define('RegExp', function(obj) {
+    assert(obj).is(assert.structure({
+      single: window.RegExp,
+      multiple: window.RegExp
+    }));
+  });
+} else {
+  RegExp = {};
 }
 
-export var RegExp = assert.define('RegExp', function(obj) {
-  assert(obj).is(assert.structure({
-    single: window.RegExp,
-    multiple: window.RegExp
-  }));
-});
-
 export class RegExpWrapper {
   static create(regExpStr, flags:string = ''):RegExp {
     flags = flags.replace(/g/g, '');
@@ -224,12 +236,7 @@ export function isJsObject(o):boolean {
 }
 
 export function assertionsEnabled():boolean {
-  try {
-    var x:int = "string";
-    return false;
-  } catch (e) {
-    return true;
-  }
+  return assertionsEnabled_;
 }
 
 export function print(obj) {