Enable the IAT patcher unittests in x64.

syzygy/pe/export_dll_x64.def

Index: syzygy/pe/export_dll_x64.def
diff --git a/syzygy/pe/export_dll.def b/syzygy/pe/export_dll_x64.def
similarity index 82%
copy from syzygy/pe/export_dll.def
copy to syzygy/pe/export_dll_x64.def
index f8ef379e81e361f52ff3aa28b6a6e333ec386d27..eeebd424a3ea7cc502043d788f2457e9d049dc8b 100644
--- a/syzygy/pe/export_dll.def
+++ b/syzygy/pe/export_dll_x64.def
@@ -1,4 +1,4 @@
-; Copyright 2010 Google Inc. All Rights Reserved.
+; Copyright 2016 Google Inc. All Rights Reserved.
 ;
 ; Licensed under the Apache License, Version 2.0 (the "License");
 ; you may not use this file except in compliance with the License.
@@ -12,12 +12,12 @@
 ; See the License for the specific language governing permissions and
 ; limitations under the License.
 ;
-; Export declarations for the export DLL.
-LIBRARY export_dll.dll
+; Export declarations for the export DLL 64-bit build.
+LIBRARY export_dll_x64.dll
 
 EXPORTS
   ; Export some functions to make sure the DLL has an exports section.
   kExportedData
   function1
   function2 @7 NONAME
-  function3
+  function3