[SYCL] Add a regression test for kernel names.

Added a regression test to confirm the lack of ambiguity in
the integration header for kernel names declared within
namespaces in case of namespaces with matching names.

Signed-off-by: Alexey Voronov <[email protected]>

Author: alexeyvoronov-intel

sycl/test/regression/kernel_name_inside_sycl_namespace.cpp

@@ -0,0 +1,31 @@
+// RUN: %clangxx -fsycl %s -o %t.out
+// RUN: env SYCL_DEVICE_TYPE=HOST %t.out
+// RUN: %CPU_RUN_PLACEHOLDER %t.out
+// RUN: %GPU_RUN_PLACEHOLDER %t.out
+// RUN: %ACC_RUN_PLACEHOLDER %t.out
+
+//==------- kernel_name_inside_sycl_namespace.cpp - Regression 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
+//
+//===----------------------------------------------------------------------===//
+
+#include <CL/sycl.hpp>
+
+struct A {};
+namespace sycl {
+struct B {};
+using b_t = B;
+using a_t = A;
+} // namespace sycl
+
+int main() {
+  cl::sycl::queue Queue;
+  Queue.submit(
+      [&](cl::sycl::handler &CGH) { CGH.single_task<sycl::b_t>([=]() {}); });
+  Queue.submit(
+      [&](cl::sycl::handler &CGH) { CGH.single_task<sycl::a_t>([=]() {}); });
+  return 0;
+}