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

tests/compiler/dart2js/simple_inferrer_postfix_prefix_test.dart

Index: tests/compiler/dart2js/simple_inferrer_postfix_prefix_test.dart
diff --git a/tests/compiler/dart2js/simple_inferrer_postfix_prefix_test.dart b/tests/compiler/dart2js/simple_inferrer_postfix_prefix_test.dart
index 3c9aaa15eefd9e9423032cb833ca09f388714739..cfae3a72e89cbf8af8bfe06089c2395e1d71b518 100644
--- a/tests/compiler/dart2js/simple_inferrer_postfix_prefix_test.dart
+++ b/tests/compiler/dart2js/simple_inferrer_postfix_prefix_test.dart
@@ -61,7 +61,7 @@ main() {
 """;
 
 void main() {
-  Uri uri = new Uri.fromComponents(scheme: 'source');
+  Uri uri = new Uri(scheme: 'source');
   var compiler = compilerFor(TEST, uri);
   compiler.runCompiler(uri);
   var typesInferrer = compiler.typesTask.typesInferrer;