[llvm-pdbutil] Add back the ability to dump hashes and index offsets.

This was regressed in a previous patch that re-wrote the dumper,
and I'm incrementally adding back the pieces that are missing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305524 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed