Get rid of android_lookup_method

Get rid of android_lookup_method

* src/android.c (struct android_emacs_window): New methods.
(android_init_emacs_window): Add new methods.
(android_lookup_method): Delete now-unused function.
(android_change_window_attributes, android_reparent_window)
(android_map_window, android_unmap_window, android_resize_window)
(android_move_window, android_set_input_focus)
(android_raise_window, android_lower_window, android_get_geometry)
(android_translate_coordinates, android_set_dont_focus_on_map)
(android_set_dont_accept_focus): Don't look up the class and
method each time when calling a function; that's just waste.