Add minidump support to obj2yaml
This patch adds the code needed to parse a minidump file into the
MinidumpYAML model, and the necessary glue code so that obj2yaml can
recognise the minidump files and process them.
Reviewers: jhenderson, zturner, clayborg
Subscribers: mgorny, lldb-commits, amccarth, markmentovai, aprantl, llvm-commits
Differential Revision: https://reviews.llvm.org/D59634