fix some errors in our SDK, mostly around numbers

tool/input_sdk/private/js_string.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart._interceptors;
 
 /**
  * The interceptor class for [String]. The compiler recognizes this
  * class as an interceptor, and changes references to [:this:] to
  * actually use the receiver of the method, which is generated as an extra
  * argument added to each member.
  */
 @JsPeerInterface(name: 'String')
 class JSString extends Interceptor implements String, JSIndexable {
   const JSString();
 
   int codeUnitAt(int index) {
     if (index is !int) throw new ArgumentError(index);
     if (index < 0) throw new RangeError.value(index);
     if (index >= length) throw new RangeError.value(index);
-    return JS('JSUInt31', r'#.charCodeAt(#)', this, index);
+    return JS('int', r'#.charCodeAt(#)', this, index);
   }
 
   Iterable<Match> allMatches(String string, [int start = 0]) {
     checkString(string);
     checkInt(start);
     if (0 > start || start > string.length) {
       throw new RangeError.range(start, 0, string.length);
     }
     return allMatchesInStringUnchecked(this, string, start);
   }
@@ skipping 294 matching lines @@
     }
 
     if (endIndex == result.length) return result;
     if (endIndex == 0) return "";
     return JS('String', r'#.substring(#, #)', result, 0, endIndex);
   }
 
   String operator*(int times) {
     if (0 >= times) return '';  // Unnecessary but hoists argument type check.
     if (times == 1 || this.length == 0) return this;
-    if (times != JS('JSUInt32', '# >>> 0', times)) {
+    if (times != JS('int', '# >>> 0', times)) {
       // times >= 2^32. We can't create a string that big.
       throw const OutOfMemoryError();
     }
     var result = '';
-    var s = this;
+    String s = this;
     while (true) {
       if (times & 1 == 1) result = s + result;
-      times = JS('JSUInt31', '# >>> 1', times);
+      times = JS('int', '# >>> 1', times);
       if (times == 0) break;
       s += s;
     }
     return result;
   }
 
   String padLeft(int width, [String padding = ' ']) {
     int delta = width - this.length;
     if (delta <= 0) return this;
     return padding * delta + this;
@@ skipping 108 matching lines @@
  */
 class _CodeUnits extends UnmodifiableListBase<int> {
   /** The string that this is the code units of. */
   String _string;
 
   _CodeUnits(this._string);
 
   int get length => _string.length;
   int operator[](int i) => _string.codeUnitAt(i);
 }