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/RefQuantizeWorkload.hpp b/src/backends/reference/workloads/RefQuantizeWorkload.hpp
index 9ae1076..48116e7 100644
--- a/src/backends/reference/workloads/RefQuantizeWorkload.hpp
+++ b/src/backends/reference/workloads/RefQuantizeWorkload.hpp
@@ -16,13 +16,11 @@
 {
 public:
     RefQuantizeWorkload(const QuantizeQueueDescriptor& descriptor, const WorkloadInfo &info);
-    void PostAllocationConfigure() override;
     void Execute() const override;
+    void ExecuteAsync(WorkingMemDescriptor& workingMemDescriptor)  override;
 
 private:
-
-    std::unique_ptr<Decoder<float>> m_InputDecoder;
-    std::unique_ptr<Encoder<float>> m_OutputEncoder;
+    void Execute(std::vector<ITensorHandle*> inputs, std::vector<ITensorHandle*> outputs) const;
 
     size_t m_NumElements;
 };