Remove obsolete Android script StartShell argument.

I meant to remove this in https://codereview.chromium.org/1138933004

BUG=486220
TEST=Android apptest runner doesn't crash with argument error.
TBR=sky@chromium.org

Review URL: https://codereview.chromium.org/1124103008

Cr-Commit-Position: refs/heads/master@{#329898}

mojo/tools/mopy/test_util.py

@@ -55,7 +55,7 @@ def run_test_android(shell, shell_args, apps_and_args):
       _logger.debug("Starting shell with arguments: %s" % arguments)
       start_time = time.time()
       # TODO(vtl): Do more logging in lower layers.
-      shell.StartShell(arguments, wf, wf.close, False)
+      shell.StartShell(arguments, wf, wf.close)
       rv = rf.read()
       run_time = time.time() - start_time
       _logger.debug("Shell completed")