[Clang][Sanitizers] Expect test failure on {arm,thumb}v7

Summary:
Versions of LLVM built on {arm,thumb}v7 appear to have differently
configured pass managers, which causes restrictions on which sanitizers
we may use.

As such, expect failure of the recently added "sanitize-coverage.c" test
on these architectures until we can investigate armv7's restrictions.

Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=46117

Reviewers: vitalybuka, glider

Reviewed By: glider

Subscribers: glider, kristof.beyls, danielkiss, cfe-commits, vvereschaka

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80668