Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/server_options_test.dart

Index: pkg/analysis_server/test/server_options_test.dart
diff --git a/pkg/analysis_server/test/server_options_test.dart b/pkg/analysis_server/test/server_options_test.dart
index 4a32152bbb48b320606d7c639a71ad7477ef2cb8..b5a0072c3b83fe6a3f6cf6dcf34f3d0a4d0d3f09 100644
--- a/pkg/analysis_server/test/server_options_test.dart
+++ b/pkg/analysis_server/test/server_options_test.dart
@@ -8,7 +8,7 @@
 library analysis_server.test.server_options;
 
 import 'package:analysis_server/src/server_options.dart';
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 
 import 'utils.dart';
 
@@ -19,7 +19,7 @@ void main() {
     test('basic - []', () {
       var options = new ServerOptions.fromContents('''# ignored
 foo: bar
-baz: padded   
+baz: padded

[Paul Berry, 2016/10/06 15:55:45]

Don't delete the end of line space here.  It's necessary for the test, because
the test is verifying that ServerOptions.fromContents properly strips the end of
line space.

[scheglov, 2016/10/06 17:17:07]

OK

I changed the code to make it resilient to formatting in
https://codereview.chromium.org/2402483002

 ''');
       expect(options['foo'], equals('bar'));
       expect(options['baz'], equals('padded'));