Fix clang-tidy errors

Resolve the following clang-tidy errors:

* use of undeclared identifier 'ARM_COMPUTE_ASSERT'
* no template named 'AbsoluteTolerance'
* no template named 'RelativeTolerance'

These errors are a result of missing include headers in test fixtures.

Resolves: COMPMID-6604

Change-Id: I8058c5848bb52a44925b2f99c9e8edf84dc79acc
Signed-off-by: Jakub Sujak <jakub.sujak@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/10561
Reviewed-by: Gunes Bayir <gunes.bayir@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
diff --git a/tests/validation/fixtures/MatMulFixture.h b/tests/validation/fixtures/MatMulFixture.h
index e6b28f5..2e79612 100644
--- a/tests/validation/fixtures/MatMulFixture.h
+++ b/tests/validation/fixtures/MatMulFixture.h
@@ -21,14 +21,16 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-#ifndef ACL_TESTS_VALIDATION_FIXTURES_MATMULFIXTURE
-#define ACL_TESTS_VALIDATION_FIXTURES_MATMULFIXTURE
+#ifndef ACL_TESTS_VALIDATION_FIXTURES_MATMULFIXTURE_H
+#define ACL_TESTS_VALIDATION_FIXTURES_MATMULFIXTURE_H
 
 #include "arm_compute/core/Types.h"
 #include "arm_compute/core/Utils.h"
 #include "arm_compute/core/utils/quantization/AsymmHelpers.h"
 #include "src/core/utils/quantization/AsymmHelpers.h"
+#include "tests/framework/Asserts.h" // Required for ARM_COMPUTE_ASSERT
 #include "tests/framework/Fixture.h"
+#include "tests/validation/Validation.h"
 #include "tests/validation/reference/ActivationLayer.h"
 #include "tests/validation/reference/GEMM.h"
 #include "tests/validation/reference/GEMMLowp.h"
@@ -338,4 +340,4 @@
 } // namespace validation
 } // namespace test
 } // namespace arm_compute
-#endif /* ACL_TESTS_VALIDATION_FIXTURES_MATMULFIXTURE */
+#endif // ACL_TESTS_VALIDATION_FIXTURES_MATMULFIXTURE_H