Build only the appropriate x86 arches for nacl (chrome side).

ppapi/ppapi_nacl_test_common.gypi

 # Copyright (c) 2013 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.
 
 {
   'includes': [
-    '../native_client/build/untrusted.gypi',
+    '../build/common_untrusted.gypi',
   ],
   'target_defaults': {
     # We need to override the variables in untrusted.gypi outside of a
     # target_condition block because the target_condition block in
     # untrusted gypi is fully evaluated and interpolated before any of the
     # target_condition blocks in this file are expanded.  This means that any
     # variables overriden inside a target_condition block in this file will not
     # affect the values in untrusted.gypi.
     'variables': {
       'test_files': [],
@@ skipping 209 matching lines @@
                   '>@(create_nmf_args_portable)'
                 ],
               },
             ],
           }],
         ],
       }],
     ],
   },
 }