BSSN_MoL is not part of the toolkit. Many thorns which are part of the toolkit have tests which rely on BSSN_MoL. These tests currently do not run. In order to test these thorns, the tests should be updated to use ML_BSSN instead of BSSN_MoL.
Correctness-testing the new results (which will be different due to differences in the implementation of BSSN) is problematic. I propose that if the tests run with ML_BSSN and do not generate NaNs or poison, we should just commit the new test data. These are only regression tests anyway - there is no formal correctness-testing framework.