Merge the dart:uri library into dart:core and update the Uri class

tests/compiler/dart2js/gvn_dynamic_field_get_test.dart

Index: tests/compiler/dart2js/gvn_dynamic_field_get_test.dart
diff --git a/tests/compiler/dart2js/gvn_dynamic_field_get_test.dart b/tests/compiler/dart2js/gvn_dynamic_field_get_test.dart
index 739645bd6fbf8c785341cc58c6b98d16ed87be48..c1a784a38625d6ffccf149afae0ee3748966051f 100644
--- a/tests/compiler/dart2js/gvn_dynamic_field_get_test.dart
+++ b/tests/compiler/dart2js/gvn_dynamic_field_get_test.dart
@@ -22,7 +22,7 @@ main() {
 """;
 
 main() {
-  Uri uri = new Uri.fromComponents(scheme: 'source');
+  Uri uri = new Uri(scheme: 'source');
   var compiler = compilerFor(TEST, uri);
   compiler.runCompiler(uri);
   String generated = compiler.assembledCode;