[hwasan, asan] Intercept vfork.

Summary:
Intercept vfork on arm, aarch64, i386 and x86_64.

Reviewers: pcc, vitalybuka

Subscribers: kubamracek, mgorny, javed.absar, krytarowski, kristof.beyls, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D58533

Change-Id: I40a534cf1539f256bcba769360d0adf6ae16e3ab
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@355030 91177308-0d34-0410-b5e6-96231b3b80d8
23 files changed