The Hydra buildfarm provides code coverage analysis. For some reason,
in some test cases, code coverage data seem to be incompatible, and
generate error messages at parser run-time. Ignore these messages so
that (i) these tests do pass, (ii) coverage results be provided by
Hydra.
* tests/local.at (AT_PARSER_CHECK): Ignore messages for failed merges
of code coverage/profiling results.