dwarfdump: Add support for the --diff option.

--diff      Emit the output in a diff-friendly way by omitting offsets and
            addresses.

<rdar://problem/34502625>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320214 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit b5b768dedeb4ffa94b60ff0c6c19f1095964086b)
7 files changed