SDK fixes

lib/runtime/dart/_interceptors.js

 var _interceptors;
 (function(exports) {
   'use strict';
   let JSArray = Array;
   let JSMutableArray$ = dart.generic(function(E) {
     class JSMutableArray extends JSArray$(E) {}
     JSMutableArray[dart.implements] = () => [JSMutableIndexable];
     return JSMutableArray;
   });
   let JSMutableArray = JSMutableArray$();
@@ skipping 122 matching lines @@
       }
     }
     truncateToDouble() {
       return this['<'](0) ? this.ceilToDouble() : this.floorToDouble();
     }
     clamp(lowerLimit, upperLimit) {
       if (!dart.is(lowerLimit, core.num))
         throw new core.ArgumentError(lowerLimit);
       if (!dart.is(upperLimit, core.num))
         throw new core.ArgumentError(upperLimit);
-      if (dart.dsend(dart.dsend(lowerLimit, 'compareTo', upperLimit), '>', 0)) {
+      if (dart.notNull(lowerLimit.compareTo(upperLimit)) > 0) {
         throw new core.ArgumentError(lowerLimit);
       }
-      if (dart.notNull(this.compareTo(dart.as(lowerLimit, core.num))) < 0)
-        return dart.as(lowerLimit, core.num);
-      if (dart.notNull(this.compareTo(dart.as(upperLimit, core.num))) > 0)
-        return dart.as(upperLimit, core.num);
+      if (dart.notNull(this.compareTo(lowerLimit)) < 0)
+        return lowerLimit;
+      if (dart.notNull(this.compareTo(upperLimit)) > 0)
+        return upperLimit;
       return this;
     }
     toDouble() {
       return this;
     }
     toStringAsFixed(fractionDigits) {
       _js_helper.checkInt(fractionDigits);
       if (dart.notNull(fractionDigits) < 0 || dart.notNull(fractionDigits) > 20) {
         throw new core.RangeError(fractionDigits);
       }
@@ skipping 912 matching lines @@
   exports.findInterceptorForType = findInterceptorForType;
   exports.JSBool = JSBool;
   exports.JSNull = JSNull;
   exports.JSIndexable = JSIndexable;
   exports.JSMutableIndexable = JSMutableIndexable;
   exports.JSObject = JSObject;
   exports.JavaScriptObject = JavaScriptObject;
   exports.PlainJavaScriptObject = PlainJavaScriptObject;
   exports.UnknownJavaScriptObject = UnknownJavaScriptObject;
 })(_interceptors || (_interceptors = {}));