[GWP-ASan] Integration with Scudo .
See D60593 for further information.
This patch adds GWP-ASan support to the Scudo hardened allocator. It also
implements end-to-end integration tests using Scudo as the backing allocator.
The tests include crash handling for buffer over/underflow as well as
Reviewers: vlad.tsyrklevich, cryptoad
Reviewed By: vlad.tsyrklevich, cryptoad
Subscribers: kubamracek, mgorny, #sanitizers, llvm-commits, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D62929