COFF: migrate def parser from LLD to LLVM [1/2]

This is split up into two commits.
The will create the DEF parser in LLVM.
Check the following commit to see the removal from LLD

Reviewers: ruiu

Differential Revision: https://reviews.llvm.org/D32689

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303490 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed