checking for test naming collisions needs improvements with Params tests - can lead to vague error messages for params

[georgejecook]

Naming collisions for tests need better handling. If a naming collision occurs for a test with params, and there is a mismatch in param types, then it can lead to unclear crash scenarios because the params test is still added, so it is applied to the original (collided) test case.

Need to take care to ensure that any params test case, which is part of a name-collided test does not get added.