Fix directory layout for tools/memory_inspector tests.

tools/memory_inspector/PRESUBMIT.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Top-level presubmit script for memory_inspector.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
 details on the presubmit API built into gcl.
 """
 
 
 def CommonChecks(input_api, output_api):
   output = []
   output.extend(input_api.canned_checks.RunPylint(input_api, output_api))
-  output.extend(
-      input_api.canned_checks.RunUnitTestsInDirectory(
-          input_api, output_api,
-          input_api.os_path.join(input_api.PresubmitLocalPath(), 'tests'),
-          whitelist=[r'.+_test\.py$']))
+  output.extend(input_api.canned_checks.RunUnitTests(
+      input_api,
+      output_api,
+      [input_api.os_path.join(input_api.PresubmitLocalPath(), 'run_tests')]))
 
   if input_api.is_committing:
     output.extend(input_api.canned_checks.PanProjectChecks(input_api,
                                                            output_api,
                                                            owners_check=False))
   return output
 
 
 def CheckChangeOnUpload(input_api, output_api):
   return CommonChecks(input_api, output_api)
 
 
 def CheckChangeOnCommit(input_api, output_api):
   return CommonChecks(input_api, output_api)