Update test.py's --arch=all to match that of build.py.

tools/testing/dart/options.dart

 // Copyright (c) 2013, 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:io';
 
 import 'configuration.dart';
 import 'drt_updater.dart';
 import 'path.dart';
 import 'test_suite.dart';
@@ skipping 544 matching lines @@
       // Install the runtime if needed.
       var updater = runtimeUpdater(
           runtime, data["drt"] as String, data["dartium"] as String);
       if (updater != null) {
         updater.update();
       }
 
       // Expand architectures.
       var architectures = data["arch"] as String;
       if (architectures == "all") {
-        architectures = "ia32,x64,simarm,simarm64,simmips,simdbc64";
+        architectures = "ia32,x64,simarm,simarm64,simdbc64";
       }
 
       for (var architectureName in architectures.split(",")) {
         var architecture = Architecture.find(architectureName);
 
         // Expand compilers.
         var compilers = data["compiler"] as String;
         for (var compilerName in compilers.split(",")) {
           var compiler = Compiler.find(compilerName);
 
@@ skipping 194 matching lines @@
       if (name == option.name) return option;
 
       // Allow hyphens instead of underscores as the separator since they are
       // more common for command line flags.
       if (name == option.name.replaceAll("_", "-")) return option;
     }
 
     return null;
   }
 }