IVGCVSW-3231 Add reference workload support for SpaceToDepth

* Added reference workload for SpaceToDepth
* Added unit tests for float32 & uint8
* Minor sort refactoring to RefWorkloads.hpp to alphabetical order

Change-Id: I2e01f8101650e2aae102a8a32bc0064f067141ab
Signed-off-by: Keith Davis <keith.davis@arm.com>
diff --git a/src/backends/reference/workloads/RefSpaceToDepthWorkload.hpp b/src/backends/reference/workloads/RefSpaceToDepthWorkload.hpp
new file mode 100644
index 0000000..82d8528
--- /dev/null
+++ b/src/backends/reference/workloads/RefSpaceToDepthWorkload.hpp
@@ -0,0 +1,21 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+#pragma once
+
+#include "backendsCommon/Workload.hpp"
+
+#include <armnn/TypesUtils.hpp>
+
+namespace armnn
+{
+
+class RefSpaceToDepthWorkload : public BaseWorkload<SpaceToDepthQueueDescriptor>
+{
+public:
+    using BaseWorkload<SpaceToDepthQueueDescriptor>::BaseWorkload;
+    virtual void Execute() const override;
+};
+
+} //namespace armnn