Get rid of an unused library.

lib/src/runner/load_exception_suite.dart

-// Copyright (c) 2015, 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.runner.load_exception_suite;
-
-import 'dart:async';
-
-import '../backend/group.dart';
-import '../backend/invoker.dart';
-import '../backend/metadata.dart';
-import '../backend/suite.dart';
-import 'load_exception.dart';
-
-/// A test suite generated from a load exception.
-///
-/// Load exceptions are exposed as test suites so that they can be presented
-/// alongside successful tests.
-class LoadExceptionSuite extends Suite {
-  /// The exception that this suite exposes.
-  final LoadException exception;
-  final StackTrace stackTrace;
-
-  LoadExceptionSuite(LoadException exception, stackTrace)
-      : exception = exception,
-        stackTrace = stackTrace,
-        super(new Group.root([
-          new LocalTest("load error", new Metadata(),
-              () => new Future.error(exception, stackTrace))
-        ]), path: exception.path);
-}