dwarfdump: -summarize-types: print a short summary (unqualified type name,...

dwarfdump: -summarize-types: print a short summary (unqualified type name, hash, length) of type units rather than dumping contents

This is just a quick utility handy for getting rough summaries of types
in a given object or dwo file. I've been using it to investigate the
amount of type info redundancy across a project build, for example.

llvm-svn: 284537