TEST: Allow parameter_space to work on repeated calls of test
TEST: Allow parameter_space to work on repeated calls of test

If we have a test that's being called more than once (i.e. two
test cases, both subclasses of the same base test case, with
different setup but calling the same test), allow the subsequent
calls to re-consume the same params

alphaBenj/zipline,humdings/zipline,bartosh/zipline,Scapogo/zipline,humdings/zipline,enigmampc/catalyst,bartosh/zipline,florentchandelier/zipline,quantopian/zipline,florentchandelier/zipline,quantopian/zipline,enigmampc/catalyst,Scapogo/zipline,alphaBenj/zipline