aliases.
 - Attributes specific to a definition are only set when the
   definition is seen.
 - Alias generation is delayed until the end of the module; necessary
   since the alias may reference forward.
 - Fixes: PR2743, <rdr://6140807&6094512>
 - Improves: <rdr://6095112> (added XFAIL)

Also, print module on verification failures.

llvm-svn: 55966