[SYCL][E2E] Disable Matrix/XMX8/element_wise_all_sizes.cpp on DG2 (#11934)

This commit disables the Matrix/XMX8/element_wise_all_sizes.cpp on DG2.
It was already known to fail, but has also been seen to regularly time
out in CI.

---------

Signed-off-by: Larsen, Steffen <steffen.larsen@intel.com>

Author: steffenlarsen

sycl/test-e2e/Matrix/XMX8/element_wise_all_sizes.cpp

@@ -6,7 +6,10 @@
 //
 //===----------------------------------------------------------------------===//
 // REQUIRES: matrix-xmx8
-// XFAIL: gpu-intel-dg2
+
+// TODO: Currently fails and regularly times out on DG2. Re-enable when this has
+//       been addressed.
+// UNSUPPORTED: gpu-intel-dg2
 
 // RUN: %{build} -o %t.out
 // RUN: %{run} %t.out