[X86] Fix SJLJ struct offsets for x86_64

This is necessary, but not sufficient, for having working SJLJ exception
handling on x86_64.

Differential Revision: https://reviews.llvm.org/D38254

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314277 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed