Wiredtiger has the ability to automatically configure a periodic checkpointing thread, similar to the server. It is a problem to allow users to configure both.

WT: checkpointer is documented here: https://github.com/wiredtiger/wiredtiger/blob/3b4b3cadd094fc4c0d3f5a026e1f3884e3dd9e3a/dist/api_data.py#L560

For simplicity's sake, start by assuming any time `checkpoint=` is set, that is a problem. If that proves insufficient, use the config parser https://source.wiredtiger.com/develop/struct_w_t___c_o_n_f_i_g___p_a_r_s_e_r.html 

There is precedent for something like this here: https://github.com/10gen/mongo/blob/46e7d497f02b19fb8089462835e65448cef7b4b5/src/mongo/db/storage/wiredtiger/wiredtiger_kv_engine.cpp#L3076 

Ideally this would be an error, but it is unclear how often users configure this in practice, so we might need to treat it as a warning.