IVGCVSW-5410 Move ILayerSupport.hpp to backends folder

 * ILayerSupport is a backend interface, and so in order 
   to prevent false positives in ABI Compliance Checker 
   move it to backends folder.
 * Front end users should use ABI stable 
   GetILayerSupportByBackendId which takes 
   advantage of LayerSupportHandle

Signed-off-by: Francis Murtagh <francis.murtagh@arm.com>
Change-Id: Ie119451c5d55f114525dc79b6f3474b2df7e3418
!android-nn-driver:5516
diff --git a/src/backends/backendsCommon/test/DynamicBackendTests.hpp b/src/backends/backendsCommon/test/DynamicBackendTests.hpp
index 090488e..8302bfd 100644
--- a/src/backends/backendsCommon/test/DynamicBackendTests.hpp
+++ b/src/backends/backendsCommon/test/DynamicBackendTests.hpp
@@ -7,7 +7,7 @@
 
 #include <armnn/BackendRegistry.hpp>
 #include <armnn/backends/DynamicBackend.hpp>
-#include <armnn/ILayerSupport.hpp>
+#include <armnn/backends/ILayerSupport.hpp>
 #include <armnn/utility/PolymorphicDowncast.hpp>
 #include <backendsCommon/CpuTensorHandle.hpp>
 #include <backendsCommon/DynamicBackendUtils.hpp>