IVGCVSW-3878 Add reference workload for SLICE

* Added reference workload implementation and layer tests
  for all supported tensor dimensions (1d, 2d, 3d, 4d)

Signed-off-by: Aron Virginas-Tar <Aron.Virginas-Tar@arm.com>
Change-Id: I40eb300828933e9183027281105d1a7e597d1569
diff --git a/src/backends/reference/workloads/CMakeLists.txt b/src/backends/reference/workloads/CMakeLists.txt
index 23d6024..3077095 100644
--- a/src/backends/reference/workloads/CMakeLists.txt
+++ b/src/backends/reference/workloads/CMakeLists.txt
@@ -107,6 +107,8 @@
     RefResizeWorkload.hpp
     RefRsqrtWorkload.cpp
     RefRsqrtWorkload.hpp
+    RefSliceWorkload.cpp
+    RefSliceWorkload.hpp
     RefSoftmaxWorkload.cpp
     RefSoftmaxWorkload.hpp
     RefSpaceToBatchNdWorkload.cpp
@@ -127,6 +129,8 @@
     Resize.hpp
     Rsqrt.cpp
     Rsqrt.hpp
+    Slice.cpp
+    Slice.hpp
     Softmax.cpp
     Softmax.hpp
     SpaceToBatchNd.hpp