Add tests for more complex base record types

As a developer, I would like to know if behaviour we rely on in more complex epics records (waveform, seq, aSub, dfanout, etc.) is changed by an update to epics base. We should have tests for the base functionality of these records, the database files for these tests could then also be used as an example of how to write records of these types.

### Acceptance Criteria
_What is the acceptance criteria?_
- [ ] We have generic database files that show functionality we rely on for complex record types.
- [ ] There are tests in the ioc test framework to check that this has not changed.

### Why
In the past, we have caught changes to epics base that alter the behaviour of records via our ioc tests, it would be useful to know earlier that this is due to a change in epics base rather than in the ioc.

## How to Test
_verbose instructions for reviewer to test changes
(**Add before making a PR**)_