1cdbea7f742fa128062009ea8ca22383bceacd1e bitcoinconsensus: invalid flags should be set to bitcoinconsensus_error type, add test cases covering bitcoinconsensus error codes (Thomas Kerin) Pull request description: Backport of #13655 to 0.16 Tree-SHA512: b62e185f2aa957f09255090e59f96c039f47a5623d68b6fef8d1dd831c6d3135b039be5cfad0f823687ff2a5143d24e34bd83fefcc9ba5b68f43054cbd9d909d