Update slave scripts to set skia_arch_type but not skia_arch_width

scripts/slave/recipes/skia/skia.expected/Perf-Win8-MSVC-ShuttleB-GPU-HD4600-x86_64-Release-Trybot.json

 [
   {
     "cmd": [
       "git.bat",
       "fetch"
     ],
     "cwd": "[SLAVE_BUILD]\\skia",
     "name": "git fetch"
   },
   {
@@ skipping 110 matching lines @@
   {
     "cmd": [
       "python",
       "make.py",
       "nanobench",
       "BUILDTYPE=Release_x64"
     ],
     "cwd": "[SLAVE_BUILD]\\skia",
     "env": {
       "CHROME_PATH": "/home/chrome-bot/src",
-      "GYP_DEFINES": "qt_sdk=C:/Qt/Qt5.1.0/5.1.0/msvc2012_64/ skia_arch_type=x86_64 skia_arch_width=64 skia_warnings_as_errors=0 skia_win_debuggers_path=c:/DbgHelp",
+      "GYP_DEFINES": "qt_sdk=C:/Qt/Qt5.1.0/5.1.0/msvc2012_64/ skia_arch_type=x86_64 skia_warnings_as_errors=0 skia_win_debuggers_path=c:/DbgHelp",
       "SKIA_OUT": "[SLAVE_BUILD]\\skia\\out\\Perf-Win8-MSVC-ShuttleB-GPU-HD4600-x86_64-Release-Trybot"
     },
     "name": "build nanobench"
   },
   {
     "cmd": [
       "python",
       "-u",
       "\nimport sys, os\npath = sys.argv[1]\nmode = int(sys.argv[2])\nif not os.path.isdir(path):\n  if os.path.exists(path):\n    print \"%s exists but is not a dir\" % path\n    sys.exit(1)\n  os.makedirs(path, mode)\n",
       "[SLAVE_BUILD]\\tmp",
@@ skipping 177 matching lines @@
       "500"
     ],
     "cwd": "[SLAVE_BUILD]\\skia",
     "env": {
       "AWS_CREDENTIAL_FILE": "[HOME]\\chromium-skia-gm.boto",
       "BOTO_CONFIG": "[HOME]\\chromium-skia-gm.boto"
     },
     "name": "Upload Nanobench Results"
   }
 ]