[SYCL] Added test for deprecated features (#435)

The test is created for the check that ABI of deprecated API is not
broken after this API was removed. Removed API was wrapped in
__SYCL_INTERNAL_API macro. Also this test checks that removed
API is working with this macro.

Signed-off-by: mdimakov <maxim.dimakov@intel.com>

Author: maximdimakov

.github/CODEOWNERS

@@ -74,3 +74,6 @@ SYCL/Basic/stream @againull
 
 #BFloat16 conversion
 SYCL/BFloat16 @AlexeySotkin @MrSidims
+
+# Deprecated features
+SYCL/DeprecatedFeatures @intel/llvm-reviewers-runtime

SYCL/DeprecatedFeatures/deprecated.cpp

@@ -0,0 +1,27 @@
+// RUN: %clangxx -D__SYCL_INTERNAL_API -fsycl -fsycl-targets=%sycl_triple %s -o %t.out
+// RUN: %CPU_RUN_PLACEHOLDER %t.out
+// RUN: %GPU_RUN_PLACEHOLDER %t.out
+// RUN: %HOST_RUN_PLACEHOLDER %t.out
+// RUN: %ACC_RUN_PLACEHOLDER %t.out
+
+//==------------- deprecated.cpp - SYCL 2020 deprecation 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>
+
+using namespace cl::sycl;
+
+int main() {
+  device Device{default_selector()};
+  platform Platform{default_selector()};
+
+  bool b = Device.has_extension("cl_intel_subgroups");
+  b = Platform.has_extension("some_extension");
+
+  return 0;
+}