IVGCVSW-5787 Add/Update Execute() implementations in RefActivationWorkload

 * Added multithreaded StridedSliceEndToEndTest

Signed-off-by: Finn Williams <Finn.Williams@arm.com>
Change-Id: I4579db7b5959e0a22256f1bda00238c22e611dec
diff --git a/src/backends/reference/workloads/Concatenate.hpp b/src/backends/reference/workloads/Concatenate.hpp
index 75e5f8c..e0264b0 100644
--- a/src/backends/reference/workloads/Concatenate.hpp
+++ b/src/backends/reference/workloads/Concatenate.hpp
@@ -10,5 +10,7 @@
 
 namespace armnn
 {
-void Concatenate(const ConcatQueueDescriptor &data);
+void Concatenate(const ConcatQueueDescriptor &data,
+                 std::vector<ITensorHandle*> inputs,
+                 std::vector<ITensorHandle*> outputs);
 } //namespace armnn