Trace test classes over DML boundary

In https://financialforce.slack.com/archives/C022SHHS48Z/p1671627116474759 there is an example of test:changed not finding a test class because of a dependency via DML. The trigger was update to add an additional validation but not all relevant tests were run because they only depend on the SObject and not the trigger code for the SObject.

Solving this generically would be very hard but I think we may be able to handle simple cases (as we find in test) classes.