[compiler-rt] Add support for relative offset adjustment in interception

Summary:
Some instructions can only be copied if the relative offset is adjusted.

This patch adds support for two common instruction.
It's quite common to have a indirect load in the prologue 
(loading the security cookie).

Reviewers: rnk

Subscribers: llvm-commits, wang0109, chrisha

Differential Revision: https://reviews.llvm.org/D22647

llvm-svn: 276336