Move long-running test to its own test-file.

tests/compiler/dart2js/serialization/test_data.dart

 // Copyright (c) 2016, 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 dart2js.serialization_test_data;
 
 const List<Test> TESTS = const <Test>[
+  // This test is very long-running and put here first to compile it on its own
+  // in compilation0_test.dart
+  const Test('Disable tree shaking through reflection', const {
+    'main.dart': '''
+import 'dart:mirrors';
+
+main() {
+  reflect(null).invoke(#toString, []).reflectee;
+}
+''',
+  }, expectedWarningCount: 1),
+
   const Test('Empty program', const {
     'main.dart': 'main() {}'
   }),
 
   const Test('Hello World', const {
     'main.dart': 'main() => print("Hello World");'
   }),
 
   const Test('Too many arguments to print', const {
     'main.dart': 'main() => print("Hello World", 0);'
@@ skipping 351 matching lines @@
 void foo() {}
 ''',
   }),
 
   const Test('fromEnvironment constants', const {
     'main.dart': '''
 main() => const String.fromEnvironment("foo");
 ''',
   }),
 
-  const Test('Disable tree shaking through reflection', const {
-    'main.dart': '''
-import 'dart:mirrors';
-
-main() {
-  reflect(null).invoke(#toString, []).reflectee;
-}
-''',
-  }, expectedWarningCount: 1),
-
   const Test('Unused noSuchMethod', const {
     'main.dart': '''
 import 'a.dart';
 
 main() {
   new A().m();
 }
 ''',
   }, preserializedSourceFiles: const {
     'a.dart': '''
@@ skipping 160 matching lines @@
   const Test(
       this.name,
       this.sourceFiles,
       {this.preserializedSourceFiles,
       this.unserializedSourceFiles,
       this.expectedErrorCount: 0,
       this.expectedWarningCount: 0,
       this.expectedHintCount: 0,
       this.expectedInfoCount: 0});
 }