Add a ppapi_unittests_run target.

ppapi/ppapi_unittests.isolate

 # Copyright (c) 2015 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.
 {
   'conditions': [
     ['OS=="linux" or OS=="mac" or OS=="win"', {
       'variables': {
         'command': [
-          '<(PRODUCT_DIR)/gn_unittests<(EXECUTABLE_SUFFIX)',
-        ],
-        'files': [
-          'format_test_data/',
+          '<(PRODUCT_DIR)/ppapi_unittests<(EXECUTABLE_SUFFIX)',
         ],
       },
     }],
   ],
   'includes': [
-    '../../base/base.isolate',
+    '../base/base.isolate',
   ],
 }