IVGCVSW-1913: Fix for ValidationTest.concat_float_3_relaxed

* Added RefPermuteFloat16Workload to serve as a fallback when CL
  does not support the required permute configuration for FP16
* Move Half.hpp to armnnUtils as the utils library should not be
  including private header files from the armnn library

Change-Id: Ibf0f698451e8406f7ed7cce470dab60b6d16361d
diff --git a/src/backends/test/LayerTests.hpp b/src/backends/test/LayerTests.hpp
index 9dc3afa..8939903 100644
--- a/src/backends/test/LayerTests.hpp
+++ b/src/backends/test/LayerTests.hpp
@@ -6,7 +6,7 @@
 
 #include "armnn/ArmNN.hpp"
 #include "armnn/Tensor.hpp"
-#include "Half.hpp"
+#include "armnnUtils/Half.hpp"
 
 #include <boost/multi_array.hpp>
 #include <boost/assert.hpp>