Run dartdevc tests on drt instead of Chrome on the bots.

tools/testing/dart/configuration.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'compiler_configuration.dart';
 import 'http_server.dart';
@@ skipping 524 matching lines @@
           Runtime.chromeOnAndroid,
           Runtime.safariMobileSim
         ];
 
       case Compiler.dart2js:
       case Compiler.dartdevc:
         // TODO(rnystrom): Expand to support other JS execution environments
         // (other browsers, d8) when tested and working.
         return const [
           Runtime.none,
+          Runtime.drt,
           Runtime.chrome,
         ];
 
       case Compiler.dart2analyzer:
         return const [Runtime.none];
       case Compiler.appJit:
       case Compiler.dartk:
         return const [Runtime.vm, Runtime.selfCheck];
       case Compiler.precompiler:
       case Compiler.dartkp:
@@ skipping 196 matching lines @@
 
       case macos:
         return 'xcodebuild/';
     }
 
     throw "unreachable";
   }
 
   String toString() => "System($name)";
 }