[asan] Use dynamic allocator space address on Android/AArch64.

Summary:
We need one library to support all of 39, 42 and 48 bit VMAs, and
there is no common address that works for all of them.

Reviewers: kcc, alekseyshl, javed.absar

Subscribers: rengolin, srhines, kubamracek, kristof.beyls, llvm-commits, cryptoad

Differential Revision: https://reviews.llvm.org/D47160

llvm-svn: 333025