IVGCVSW-3030 Add unit testing for the Optimization API

 * Added OptimizeSubgraphViewTests file covering a number of
   use cases for the Optimization API
 * Fixed a bug in the sub-graph selector algorithm that skipped the
   first layer in a sub-graph if it wasn't an input layer
 * Changed the graph splitting logic to make use of maps instead of
   unordered_maps to keep the split sub-graphs in consistent order
   between executions
 * Added more common unit test utils
 * Minor fixes to comply to the include file conventions

Change-Id: Iad464eaedd004109e5ef41aa487cea3ad86177d3
Signed-off-by: Matteo Martincigh <matteo.martincigh@arm.com>
diff --git a/src/backends/backendsCommon/test/ArithmeticTestImpl.hpp b/src/backends/backendsCommon/test/ArithmeticTestImpl.hpp
index 29dafd3..d0e85dd 100644
--- a/src/backends/backendsCommon/test/ArithmeticTestImpl.hpp
+++ b/src/backends/backendsCommon/test/ArithmeticTestImpl.hpp
@@ -4,12 +4,12 @@
 //
 #pragma once
 
+#include "CommonTestUtils.hpp"
+
 #include <ResolveType.hpp>
 
 #include <armnn/INetwork.hpp>
 
-#include <backendsCommon/test/CommonTestUtils.hpp>
-
 #include <boost/test/unit_test.hpp>
 
 #include <vector>