Remove XFAIL flag from sanitize-coverage-old-pm.c

This test has started passing consistently on 32bit arm where underlying
core is reported as Armv7 or Thumbv7.
However it still fails intermittently on 32bit AArch32 reported as Armv8l.

https://lab.llvm.org/buildbot/#/builders/190/builds/20
https://lab.llvm.org/buildbot/#/builders/170/builds/41

Author: omjavaid

clang/test/CodeGen/sanitize-coverage-old-pm.c

@@ -6,8 +6,7 @@
 // RUN: %clang %s -target x86_64-unknown-linux-gnu -emit-llvm -S -fsanitize=undefined  -fsanitize-coverage=trace-pc,trace-cmp -o - -flegacy-pass-manager | FileCheck %s --check-prefixes=CHECK,UBSAN
 //
 // Host armv7 is currently unsupported: https://bugs.llvm.org/show_bug.cgi?id=46117
-// UNSUPPORTED: armv8l
-// XFAIL: armv7, thumbv7
+// XFAIL: armv8l
 // The same issue also occurs on a riscv32 host.
 // XFAIL: riscv32