IVGCVSW-1885 add RefPadWorkload implementation and associated unit tests

 * Added RefPadWorkload implementation
 * Added unit tests and applied them to CL and Ref backends
 * Fixed a bug in ClPadWorkload

Change-Id: I8cb76bc9d60ae8a39b08d40f05d628e3b72f6410
diff --git a/src/backends/cl/test/ClLayerTests.cpp b/src/backends/cl/test/ClLayerTests.cpp
index 58aad99..0f8b75f 100755
--- a/src/backends/cl/test/ClLayerTests.cpp
+++ b/src/backends/cl/test/ClLayerTests.cpp
@@ -246,6 +246,11 @@
 ARMNN_AUTO_TEST_CASE(SimpleReshapeFloat32, SimpleReshapeFloat32Test)
 ARMNN_AUTO_TEST_CASE(SimpleReshapeUint8, SimpleReshapeUint8Test)
 
+// Pad
+ARMNN_AUTO_TEST_CASE(Pad2d, Pad2dTest)
+ARMNN_AUTO_TEST_CASE(Pad3d, Pad3dTest)
+ARMNN_AUTO_TEST_CASE(Pad4d, Pad4dTest)
+
 // Permute
 ARMNN_AUTO_TEST_CASE(SimplePermuteFloat32, SimplePermuteFloat32Test)
 ARMNN_AUTO_TEST_CASE(SimplePermuteUint8, SimplePermuteUint8Test)