Issue Description:

We recently hit an error where we passed an invalid module to -add_ast_path, this was completely our fault but it was a bit harder to debug because of the generic messages from LLDB. In the console once we stopped at a breakpoint you see:

path/to/binary: Cannot load Swift type information; AST validation error: The serialized module is corrupted.AST validation error: The serialized module is corrupted.

With the lldb types log we see this log

It would be great if the path to the invalid module was produced in one or both of these logs so that it would be some extra info to help debug. I was able to correlate the ordering of the logs from the types log with the output of `dsymutil -s binary | grep AST` to find the invalid module.