The distinction between comparison flags and reporting flags isn't unique

The distinction between comparison flags and reporting flags isn't unique
to unittest, so make it official:  new module constants COMPARISON_FLAGS
and REPORTING_FLAGS, which are bitmasks or'ing together the relevant
individual option flags.

set_unittest_reportflags():  Reworked to use REPORTING_FLAGS, and
simplified overly complicated flag logic.

class FakeModule:  Removed this; neither documented nor used.