[sanitizer] Remove "-android" from test_arch.

Summary:
ASan and Scudo tests are adding "-android" to test arch.
There are no tests that depend on it as far as I can see.
If necessary, do this instead:
  REQUIRES: aarch64-target-arch && android

Reviewers: pcc, vitalybuka

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

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D58532

llvm-svn: 354829