[sanitizer] Revert D50940

Summary:
The previous version of the patch makes some code unable to distinguish
failure to map address 0 and error.
Revert to turn the bots back to green while figuring out a new approach.

Reviewers: eugenis

Reviewed By: eugenis

Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D51451

llvm-svn: 340957