This commit adds a mechanism to MapperTestCase that allows implementing
test classes to check that their parameters can be updated, or throw conflict
errors as advertised. Child classes override the registerParameters method
and tell the passed-in UpdateChecker class about their parameters. Simple
conflicts can be checked, using the existing minimal mappings as a base to
compare against, or alternatively a particular initial mapping can be provided
to check edge cases (eg, norms can be updated from true to false, but not
vice versa). Updates are registered with a predicate that checks that the update
has in fact been applied to the resulting FieldMapper.
Fixes#61631
e28750b001