Clarify applicable queries in task tests

Add specific test-cases to test the applicability rule so that it can be
removed from many tests intended to test other things.  Remove the
unneeded applicable queries to simplify the other test cases. Add
comments explaining many remaining applicable queries that are still
needed.

Change-Id: I0a7ebb48806d40270b17ef8adcf267100d21c42c
3 files changed