llvm-pdbdump: Add more comprehensive dumping of symbol types.

llvm-pdbdump: Add more comprehensive dumping of symbol types.

In particular this patch adds the ability to dump complete
function signature information including argument types as
correctly formatted strings.  A side effect of this is that
almost all symbol and meta types are now formatted.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229076 91177308-0d34-0410-b5e6-96231b3b80d8