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/unit_test/program/program_info_from_patchtokens_tests.cpp

@@ -14,7 +14,6 @@
 #include "shared/test/unit_test/device_binary_format/patchtokens_tests.h"
 
 #include "RelocationInfo.h"
-#include "gmock/gmock.h"
 #include "gtest/gtest.h"
 
 TEST(PopulateProgramInfoFromPatchtokensTests, WhenRequiresLocalMemoryWindowVAIsCalledThenReturnsTrueOnlyIfAnyOfKernelsRequireLocalMemoryWindowVA) {

shared/test/unit_test/program/program_info_tests.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2020-2021 Intel Corporation
+ * Copyright (C) 2020-2022 Intel Corporation
  *
  * SPDX-License-Identifier: MIT
  *
@@ -8,7 +8,6 @@
 #include "shared/source/program/kernel_info.h"
 #include "shared/source/program/program_info.h"
 
-#include "gmock/gmock.h"
 #include "gtest/gtest.h"
 
 TEST(ProgramInfoTests, WhenPrepareLinkerInputStorageGetsCalledTwiceThenLinkerInputStorageIsReused) {

shared/test/unit_test/program/program_initialization_tests.cpp

@@ -14,7 +14,6 @@
 #include "shared/test/common/test_macros/test_checks_shared.h"
 #include "shared/test/unit_test/compiler_interface/linker_mock.h"
 
-#include "gmock/gmock.h"
 #include "gtest/gtest.h"
 
 #include <cstdint>