[COFF] Expose the PE debug data directory and dump it

This directory is used to find if there is a PDB associated with an
executable. I plan to use this functionality to teach llvm-symbolizer
whether it should use DIA or DWARF to symbolize a given DLL.

Reviewers: majnemer

Differential Revision: http://reviews.llvm.org/D20885

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271539 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed