When cleaning up type names in `unittest::base_class_name`, only call `std::string::replace` if we found the substring we are looking to replace.
When cleaning up type names in `unittest::base_class_name`, only call
`std::string::replace` if we found the substring we are looking to replace.

Reviewed-by: David Olsen <c006f74ad218cd79aa222eb0f74d6fabc2b85975@nvidia.com>
Reviewed-by: Michał 'Griwes' Dominiak <909abbecff03a37cd6bf7f670c6cf23299064dc4@griwes.info>

jaredhoberock/thrust,jaredhoberock/thrust,andrewcorrigan/thrust-multi-permutation-iterator,thrust/thrust,thrust/thrust,thrust/thrust,jaredhoberock/thrust,andrewcorrigan/thrust-multi-permutation-iterator,jaredhoberock/thrust,andrewcorrigan/thrust-multi-permutation-iterator,thrust/thrust,jaredhoberock/thrust,thrust/thrust