Added initial set of tests for the cl_khr_semaphore extension (#1428)

* Added initial set of tests for the cl_khr_semaphore extension

* Fixes to address first round of reviews for cl_khr_semaphore tests

test_common/harness/extensionHelpers.h

@@ -0,0 +1,36 @@
+//
+// Copyright (c) 2022 The Khronos Group Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#ifndef _extensionHelpers_h
+#define _extensionHelpers_h
+
+// Load a specific function that is part of an OpenCL extension
+#define GET_PFN(device, fn_name)                                               \
+    fn_name##_fn fn_name = reinterpret_cast<fn_name##_fn>(                     \
+        clGetExtensionFunctionAddressForPlatform(                              \
+            getPlatformFromDevice(device), #fn_name));                         \
+    do                                                                         \
+    {                                                                          \
+        if (!fn_name)                                                          \
+        {                                                                      \
+            log_error(                                                         \
+                "ERROR: Failed to get function pointer for %s at %s:%d\n",     \
+                #fn_name, __FILE__, __LINE__);                                 \
+            return TEST_FAIL;                                                  \
+        }                                                                      \
+    } while (false)
+
+
+#endif // _extensionHelpers_h