Provide tests for fusing pad layer in graph API

There are two tests:
    - A unit test that checks if certain padding configurations are to be
      fused or not
    - A fixture test that compares a reference implementation of pad+conv
      vs target implementation using the same fusing logic as graph API

Tests are written for CL backend only to prevent code duplication.
The code written in the graph API remains untested.

Resolves: COMPMID-4702
Change-Id: Ie84d1cb910013033b46ac9d66cf5fc556d4963d2
Signed-off-by: Gunes Bayir <gunes.bayir@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/6252
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Sheri Zhang <sheri.zhang@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/graph/Utils.cpp b/src/graph/Utils.cpp
index 7db06b9..dcab177 100644
--- a/src/graph/Utils.cpp
+++ b/src/graph/Utils.cpp
@@ -225,5 +225,6 @@
         tensor->set_handle(std::move(handle));
     }
 }
+
 } // namespace graph
 } // namespace arm_compute