Convert dart_utils.js to input_sdk/lib/_internal/utils.dart (#310)

test/codegen/expect/collection/src/unmodifiable_wrappers.js

 dart_library.library('collection/src/unmodifiable_wrappers', null, /* Imports */[
   "dart/_runtime",
   'dart/collection',
   'dart/core'
 ], /* Lazy imports */[
   'collection/wrappers'
 ], function(exports, dart, collection, core, wrappers) {
   'use strict';
   let dartx = dart.dartx;
-  dart.export(exports, collection, ['UnmodifiableListView', 'UnmodifiableMapView'], []);
+  dart.export_(exports, collection, ['UnmodifiableListView', 'UnmodifiableMapView'], []);
   const NonGrowableListMixin$ = dart.generic(function(E) {
     class NonGrowableListMixin extends core.Object {
       static _throw() {
         dart.throw(new core.UnsupportedError("Cannot change the length of a fixed-length list"));
       }
       set length(newLength) {
         return NonGrowableListMixin$()._throw();
       }
       add(value) {
         dart.as(value, E);
@@ skipping 199 matching lines @@
   // Exports:
   exports.NonGrowableListMixin$ = NonGrowableListMixin$;
   exports.NonGrowableListMixin = NonGrowableListMixin;
   exports.NonGrowableListView$ = NonGrowableListView$;
   exports.UnmodifiableSetMixin$ = UnmodifiableSetMixin$;
   exports.UnmodifiableSetMixin = UnmodifiableSetMixin;
   exports.UnmodifiableSetView$ = UnmodifiableSetView$;
   exports.UnmodifiableMapMixin$ = UnmodifiableMapMixin$;
   exports.UnmodifiableMapMixin = UnmodifiableMapMixin;
 });