[Object/ELF] - Do not crash on invalid sh_offset value of REL[A] section.

Previously code would access invalid memory and may crash,
patch fixes the issue.

Differential revision: https://reviews.llvm.org/D25187

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283204 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed