[llvm-objdump] Add `Version Definitions` dumper

Summary: `llvm-objdump` needs a `Version Definitions` dumper.

Reviewers: grimar, jhenderson

Reviewed By: grimar, jhenderson

Subscribers: rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58615

llvm-svn: 354871