Revert "Access to imports in the VM's runtime mirrors. Extend test coverage of the source mirrors."

tests/lib/mirrors/library_imports_metadata.dart

Index: tests/lib/mirrors/library_imports_metadata.dart
diff --git a/tests/lib/mirrors/library_imports_metadata.dart b/tests/lib/mirrors/library_imports_metadata.dart
deleted file mode 100644
index 9507269f47568c6d06a92b099330c183aaaa9ef4..0000000000000000000000000000000000000000
--- a/tests/lib/mirrors/library_imports_metadata.dart
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-library library_imports_metadata;
-
-@m1
-import 'dart:mirrors' as mirrors;
-
-@m2 @m3
-import 'dart:collection';
-
-import 'dart:async';
-
-const m1 = const Object();
-const m2 = const Object();
-const m3 = const Object();