Disable syzygy for Win64.

build/all.gyp

 # Copyright (c) 2012 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.
 
 {
   'targets': [
     {
       'target_name': 'All',
       'type': 'none',
       'xcode_create_dependents_test_runner': 1,
@@ skipping 165 matching lines @@
           'dependencies': [
             '../ui/app_list/app_list.gyp:*',
           ],
         }],
       ],
     }, # target_name: All
     {
       'target_name': 'All_syzygy',
       'type': 'none',
       'conditions': [
-        ['OS=="win" and fastbuild==0', {
+        ['OS=="win" and fastbuild==0 and target_arch=="ia32"', {
             'dependencies': [
               '../chrome/installer/mini_installer_syzygy.gyp:*',
             ],
           },
         ],
       ],
     }, # target_name: All_syzygy
     {
       'target_name': 'chromium_builder_tests',
       'type': 'none',
@@ skipping 586 matching lines @@
             '../chrome/chrome.gyp:browser_tests_run',
             '../chrome/chrome.gyp:sync_integration_tests_run',
             '../chrome/chrome.gyp:unit_tests_run',
             '../net/net.gyp:net_unittests_run',
           ],
         }, # target_name: chromium_swarm_tests
       ],
     }],
   ], # conditions
 }