Fixes Failures Nightly #818

- COMPMID-3542: Nightly failure: /tests/validation/fixtures/PixelWiseMultiplicationFixture.h error: lambda capture 'this' is not used
- COMPMID-3544: Nightly failure: undefined reference to arm_compute::test::validation::reference::arithmetic_operation<int>

Change-Id: Ia7f8a50a4debfe43dd6be41a52cf62ee3092ae6e
Signed-off-by: Manuel Bottini <manuel.bottini@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/3445
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/tests/validation/reference/ArithmeticOperations.cpp b/tests/validation/reference/ArithmeticOperations.cpp
index 40f4e64..1c62ac6 100644
--- a/tests/validation/reference/ArithmeticOperations.cpp
+++ b/tests/validation/reference/ArithmeticOperations.cpp
@@ -180,6 +180,7 @@
     }
 }
 
+template SimpleTensor<int32_t> arithmetic_operation(ArithmeticOperation op, const SimpleTensor<int32_t> &src1, const SimpleTensor<int32_t> &src2, SimpleTensor<int32_t> &dst, ConvertPolicy convert_policy);
 template SimpleTensor<half> arithmetic_operation(ArithmeticOperation op, const SimpleTensor<half> &src1, const SimpleTensor<half> &src2, SimpleTensor<half> &dst, ConvertPolicy convert_policy);
 template SimpleTensor<float> arithmetic_operation(ArithmeticOperation op, const SimpleTensor<float> &src1, const SimpleTensor<float> &src2, SimpleTensor<float> &dst, ConvertPolicy convert_policy);