Removes python_test_root flag name entirely

NOTRY=True
BUG=271802

Review URL: https://chromiumcodereview.appspot.com/23180007

git-svn-id: http://src.chromium.org/svn/trunk/src/build@218050 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/test_runner.py

@@ -218,8 +218,7 @@ def AddInstrumentationTestOptions(option_parser):
   option_parser.add_option('-p', '--python_only', action='store_true',
                            default=False,
                            help='Run only the host-driven tests.')
-  option_parser.add_option('--python_test_root', '--host-driven-root',
-                           dest='host_driven_root',
+  option_parser.add_option('--host-driven-root',
                            help='Root of the host-driven tests.')
   option_parser.add_option('-w', '--wait_debugger', dest='wait_for_debugger',
                            action='store_true',