"Add back XFAIL for flaky test"

This reverts commit b3abdbd.

Author: Chenyang-L

sycl/test-e2e/DeviceLib/cmath_test.cpp

@@ -7,6 +7,9 @@
 // RUN: %{build} -fno-builtin -fsycl-device-lib-jit-link %{mathflags} -o %t.out
 // RUN: %if !gpu %{ %{run} %t.out %}
 
+// TODO: fix unexpected intrinsic error
+// XFAIL: *
+
 #include "math_utils.hpp"
 #include <cmath>
 #include <cstdint>