IVGCVSW-2946 RefElementwiseWorkload configures prior to first execute

+ Added PostAllocationConfigure() method to workload interface
+ Elementwise function now deduces types based on Functor
- Replaced RefComparisonWorkload with RefElementwiseWorkload specialization
+ Fixed up unit tests and minor formatting

Change-Id: I33d08797767bba01cf4efb2904920ce0f950a4fe
Signed-off-by: Derek Lamberti <derek.lamberti@arm.com>
diff --git a/src/backends/reference/workloads/Maximum.hpp b/src/backends/reference/workloads/Maximum.hpp
index 524afff..97df19d 100644
--- a/src/backends/reference/workloads/Maximum.hpp
+++ b/src/backends/reference/workloads/Maximum.hpp
@@ -10,7 +10,7 @@
 namespace armnn
 {
     template<typename T>
-    struct maximum
+struct maximum : public std::binary_function<T, T, T>
     {
         T
         operator () (const T&  inputData0, const T&  inputData1) const