llvm-cvtres: Make new dupe resource error a bit friendlier

For well-known type IDs, include the name of the type.

To not duplicate the ID->name map, make llvm-readobj call this new
function as well.  It has slightly different output, so this also
requires updating a few tests.

Differential Revision: https://reviews.llvm.org/D61086

llvm-svn: 359153