[SYCL] Disable invalid_event test on accelerator on OCL BE (#652)

The test sporadically fails on accelerator, see #651 for logs.

Author: vmaksimo

SYCL/DiscardEvents/invalid_event.cpp

@@ -1,5 +1,5 @@
-// FIXME: fails on HIP
-// UNSUPPORTED: hip
+// FIXME: fails on HIP and accelerator
+// UNSUPPORTED: hip, (opencl && acc)
 // RUN: %clangxx -fsycl -fsycl-targets=%sycl_triple %s -o %t.out
 //
 // RUN: %HOST_RUN_PLACEHOLDER %t.out