Clean-Up unused code related to GMock

This commit:
- Removes usings e.g. ::testing::Return
- Removes unnecessary gmock inclues
- Replaces Gmock macros (e.g. EXPECT_THAT) with our custom implementations

Related-To: NEO-4941
Signed-off-by: Fabian Zwolinski <fabian.zwolinski@intel.com>

shared/test/common/mocks/mock_aub_file_stream.h

@@ -10,7 +10,7 @@
 #include "shared/source/command_stream/aub_command_stream_receiver.h"
 #include "shared/test/common/test_macros/mock_method_macros.h"
 
-#include "gmock/gmock.h"
+#include "gtest/gtest.h"
 
 #include <vector>
 

shared/test/common/mocks/mock_command_stream_receiver.h

@@ -18,7 +18,7 @@
 #include "shared/source/os_interface/os_context.h"
 #include "shared/test/common/helpers/dispatch_flags_helper.h"
 
-#include "gmock/gmock.h"
+#include "gtest/gtest.h"
 
 #include <optional>
 #include <vector>

shared/test/common/mocks/mock_csr.h

@@ -10,7 +10,7 @@
 #include "shared/test/common/mocks/mock_command_stream_receiver.h"
 #include "shared/test/common/test_macros/mock_method_macros.h"
 
-#include "gmock/gmock.h"
+#include "gtest/gtest.h"
 
 #include <vector>
 

shared/test/common/mocks/mock_memory_operations_handler.h

@@ -10,7 +10,7 @@
 #include "shared/source/os_interface/os_context.h"
 #include "shared/test/common/test_macros/mock_method_macros.h"
 
-#include "gmock/gmock.h"
+#include "gtest/gtest.h"
 
 namespace NEO {
 

shared/test/common/mocks/mock_tbx_csr.h

@@ -13,7 +13,7 @@
 #include "shared/source/execution_environment/execution_environment.h"
 #include "shared/source/helpers/hw_info.h"
 
-#include "gmock/gmock.h"
+#include "gtest/gtest.h"
 
 #include <string>
 

shared/test/common/mocks/windows/mock_gmm_memory_base.h

@@ -11,7 +11,7 @@
 #include "shared/test/common/test_macros/mock_method_macros.h"
 
 #include "gmm_memory.h"
-#include "gmock/gmock.h"
+#include "gtest/gtest.h"
 
 namespace NEO {