Typing fixes to eliminate casts/dcalls

lib/runtime/dart/core.js

 var core;
 (function(exports) {
   'use strict';
   class Object {
     constructor() {
       let name = this.constructor.name;
       let init = this[name];
       let result = void 0;
       if (init)
         result = init.apply(this, arguments);
@@ skipping 1266 matching lines @@
         dart.setType(list, List$(E));
         return dart.as(list, List$(E));
       }
       filled(length, fill) {
         let result = new (List$(E))(length);
         if (length != 0 && dart.notNull(fill != null)) {
           for (let i = 0; dart.notNull(i) < dart.notNull(result[$length]); i = dart.notNull(i) + 1) {
             result[$set](i, fill);
           }
         }
-        return dart.as(result, List$(E));
+        return result;
       }
       from(elements, opts) {
         let growable = opts && 'growable' in opts ? opts.growable : true;
         let list = new (List$(E))();
         for (let e of dart.as(elements, Iterable$(E))) {
           list[$add](e);
         }
         if (growable)
           return list;
         return dart.as(_internal.makeListFixedLength(list), List$(E));
@@ skipping 1199 matching lines @@
       if (fragment != null) {
         fragment = Uri._makeFragment(fragment, 0, fragment.length);
       } else if (this.hasFragment) {
         fragment = this.fragment;
       }
       return new Uri._internal(scheme, userInfo, host, port, path, query, fragment);
     }
     get pathSegments() {
       if (this[_pathSegments] == null) {
         let pathToSplit = !dart.notNull(this.path.isEmpty) && this.path.codeUnitAt(0) == Uri._SLASH ? this.path.substring(1) : this.path;
-        this[_pathSegments] = new (collection.UnmodifiableListView$(String))(pathToSplit == "" ? dart.const(dart.setType([], List$(String))) : new List$(String).from(pathToSplit.split("/")[$map](dart.bind(Uri, 'decodeComponent')), {growable: false}));
+        this[_pathSegments] = new (collection.UnmodifiableListView$(String))(pathToSplit == "" ? dart.const(dart.setType([], List$(String))) : new (List$(String)).from(pathToSplit.split("/")[$map](dart.bind(Uri, 'decodeComponent')), {growable: false}));
       }
       return this[_pathSegments];
     }
     get queryParameters() {
       if (this[_queryParameters] == null) {
         this[_queryParameters] = new (collection.UnmodifiableMapView$(String, String))(Uri.splitQueryString(this.query));
       }
       return this[_queryParameters];
     }
     static _makePort(port, scheme) {
@@ skipping 962 matching lines @@
   exports.Stopwatch = Stopwatch;
   exports.String = String;
   exports.RuneIterator = RuneIterator;
   exports.StringBuffer = StringBuffer;
   exports.StringSink = StringSink;
   exports.Symbol = Symbol;
   exports.Type = Type;
   exports.Uri = Uri;
   exports.SupportJsExtensionMethods = SupportJsExtensionMethods;
 })(core || (core = {}));