Toward a green tools/build.py -cprecompiler -rdart_precompiled:

tools/testing/dart/test_runner.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Classes and methods for executing tests.
  *
  * This module includes:
  * - Managing parallel execution of tests, including timeout checks.
  * - Evaluating the output of each test as pass/fail/crash/timeout.
@@ skipping 1661 matching lines @@
         command, exitCode, timedOut, stdout, stderr,
         time, compilationSkipped);
   } else if (command is AnalysisCommand) {
     return new AnalysisCommandOutputImpl(
         command, exitCode, timedOut, stdout, stderr,
         time, compilationSkipped);
   } else if (command is VmCommand) {
     return new VmCommandOutputImpl(
         command, exitCode, timedOut, stdout, stderr, time, pid);
   } else if (command is CompilationCommand) {
-    if (command.displayName == 'precompiler.dart' ||
+    if (command.displayName == 'precompiler' ||
         command.displayName == 'dart2snapshot') {
       return new VmCommandOutputImpl(
           command, exitCode, timedOut, stdout, stderr, time, pid);
     }
     return new CompilationCommandOutputImpl(
         command, exitCode, timedOut, stdout, stderr, time, compilationSkipped);
   } else if (command is JSCommandlineCommand) {
     return new JsCommandlineOutputImpl(
         command, exitCode, timedOut, stdout, stderr, time);
   } else if (command is PubCommand) {
@@ skipping 1273 matching lines @@
     }
   }
 
   void eventAllTestsDone() {
     for (var listener in _eventListener) {
       listener.allDone();
     }
     _allDone();
   }
 }