[llvm-readobj] Match GNU output for DT_RPATH and DT_RUNPATH when dumping dynamic symbol table.

Reviewers: jhenderson, grimar, MaskRay, rupprecht, espindola

Subscribers: emaste, nemanjai, arichardson, kbarton, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63347

llvm-svn: 363868