[SYCL][ESIMD] Split atomic_update accessor test to make CI execution faster (#13451)

Author: fineg74

sycl/test-e2e/ESIMD/unified_memory_api/atomic_update_acc.cpp

@@ -8,8 +8,6 @@
 
 // RUN: %{build} -o %t.out
 // RUN: %{run} %t.out
-// RUN: %{build} -fsycl-esimd-force-stateless-mem -o %t.out
-// RUN: %{run} %t.out
 
 #include "Inputs/atomic_update.hpp"
 

sycl/test-e2e/ESIMD/unified_memory_api/atomic_update_acc_stateless.cpp

@@ -0,0 +1,12 @@
+//==------- atomic_update_acc_stateless.cpp - DPC++ ESIMD on-device test ---==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// RUN: %{build} -fsycl-esimd-force-stateless-mem -o %t.out
+// RUN: %{run} %t.out
+
+#include "atomic_update_acc.cpp"