Use TARGET_ARCH on Windows as well

script/cibuild

@@ -19,16 +19,16 @@ def main():
     return 'Error: Can\'t find {0}'.format(S3_CREDENTIALS_FILE)
   copy_to_environment(S3_CREDENTIALS_FILE)
 
+  if 'TARGET_ARCH' in os.environ:
+    return run_ci(['-t', os.environ['TARGET_ARCH']])
+
   if sys.platform in ['win32', 'cygwin']:
     return (run_ci(['-t', 'x64']) or
             run_ci(['-t', 'ia32']))
   elif sys.platform == 'linux2':
-    if 'TARGET_ARCH' in os.environ:
-      return run_ci(['-t', os.environ['TARGET_ARCH']])
-    else:
-      return (run_ci(['-t', 'x64']) or
-              run_ci(['-t', 'ia32']) or
-              run_ci(['-t', 'arm']))
+    return (run_ci(['-t', 'x64']) or
+            run_ci(['-t', 'ia32']) or
+            run_ci(['-t', 'arm']))
   else:
     return run_ci([])