uint64_t is a typedef. int is a primitive.
The cycles tests are going to be re-used to underpin some type-graph
unit tests. The patch removes unnecessary typedefs and makes the unit
tests simpler.
The `oil_skip` test option was added for tests that don't work under OIL
but do work under OID. However, we now have two classes of `oil_skip`ped
tests: those that could be fixed, and those that will never work.
Increase clarity by not generating the tests which do not make sense at
all, leaving us with a cleaner set of skipped (and fixable) tests.