We currently use the pair (FileBasedSelectorConfig, Selector) to discover test files in resmoke for the query_tester_manual_tests and query_correctness_generated_tests suites. For some unknown reason, this resmoke Selector works fine in the case where we pass in the roots via globs that expand to directories in the suite yml config but does not work when we specify a file path via the command line invocation of resmoke.

We should create a new Selector subclass that can handle directories and also investigate why it was somewhat working in this case.