[asan] Support dynamic shadow address instrumentation
This patch is adding the support for a shadow memory with
dynamically allocated address range.
The compiler-rt needs to export a symbol containing the shadow
This is required to support ASAN on windows 64-bits.
Reviewers: kcc, rnk, vitalybuka
Subscribers: zaks.anna, kubabrecka, dberris, llvm-commits, chrisha
Differential Revision: https://reviews.llvm.org/D23354