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

tests/lib/mirrors/library_imports_metadata_test.dart

-// 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 test.library_imports;
-
-import 'dart:mirrors';
-import 'package:expect/expect.dart';
-import 'stringify.dart';
-
-import 'library_imports_metadata.dart';
-
-main() {
-  LibraryMirror lib = currentMirrorSystem().findLibrary(#library_imports_metadata);
-
-  LibraryMirror core = currentMirrorSystem().findLibrary(#dart.core);
-  LibraryMirror mirrors = currentMirrorSystem().findLibrary(#dart.mirrors);
-  LibraryMirror collection = currentMirrorSystem().findLibrary(#dart.collection);
-  LibraryMirror async = currentMirrorSystem().findLibrary(#dart.async);
-
-  Expect.setEquals([core, mirrors, collection, async],
-                   lib.libraryDependencies.map((dep) => dep.targetLibrary));
-
-  Expect.stringEquals(
-      'import dart.async\n'
-      'import dart.collection\n'
-      'import dart.core\n'
-      'import dart.mirrors as mirrors\n',
-      stringifyDependencies(lib));
-
-  Expect.listEquals(
-      [].map(reflect).toList(),
-      lib.libraryDependencies
-          .singleWhere((dep) => dep.targetLibrary == core).metadata);
-
-  Expect.listEquals(
-      [m1].map(reflect).toList(),
-      lib.libraryDependencies
-          .singleWhere((dep) => dep.targetLibrary == mirrors).metadata);
-
-  Expect.listEquals(
-      [m2, m3].map(reflect).toList(),
-      lib.libraryDependencies
-          .singleWhere((dep) => dep.targetLibrary == collection).metadata);
-
-  Expect.listEquals(
-      [].map(reflect).toList(),
-      lib.libraryDependencies
-          .singleWhere((dep) => dep.targetLibrary == async).metadata);
-}