IVGCVSW-4483 Removes boost::polymorphic_pointer_downcast

 * replace boost::polymorphic_pointer_downcast by PolymorphicPointerDowncast
 * replaced/removed includes

Signed-off-by: Jan Eilers <jan.eilers@arm.com>
Change-Id: I0ef934a3804cf05e4c38dec6c4ec49c76111a302
diff --git a/src/backends/neon/test/NeonWorkloadFactoryHelper.hpp b/src/backends/neon/test/NeonWorkloadFactoryHelper.hpp
index 708d231..8d92ddf 100644
--- a/src/backends/neon/test/NeonWorkloadFactoryHelper.hpp
+++ b/src/backends/neon/test/NeonWorkloadFactoryHelper.hpp
@@ -7,13 +7,12 @@
 
 #include <armnn/backends/IBackendInternal.hpp>
 #include <armnn/backends/IMemoryManager.hpp>
+#include <armnn/utility/PolymorphicDowncast.hpp>
 #include <backendsCommon/test/WorkloadFactoryHelper.hpp>
 
 #include <neon/NeonBackend.hpp>
 #include <neon/NeonWorkloadFactory.hpp>
 
-#include <boost/polymorphic_pointer_cast.hpp>
-
 namespace
 {
 
@@ -30,7 +29,7 @@
         const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager)
     {
         return armnn::NeonWorkloadFactory(
-            boost::polymorphic_pointer_downcast<armnn::NeonMemoryManager>(memoryManager));
+            armnn::PolymorphicPointerDowncast<armnn::NeonMemoryManager>(memoryManager));
     }
 };