add parallel insert, analyze, iow tests

1) We need a few tests, esp. for parallel case, where we verify that stats are NOT used.
Right now many code paths don't fail but return -1, null or whatever when something else is not present, so positive tests might pass because they skip the check, not because the check passes.

2) Analyze table needs a test, esp analyze table after parallel insert, and also analyze table after an invalid transaction.