IVGCVSW-4212 Example of standalone dynamic reference backend

 * Add example to build dynamic reference backend
 * Add functions to clear dynamic backends
 * Fix the error when dynamic backend is not deregistered
 * Add DYARMNN_DYNAMIC_BACKEND_ENABLED to check disable empty
   dynamic backend when dynamic backend is enabled

Signed-off-by: Narumol Prangnawarat <narumol.prangnawarat@arm.com>
Change-Id: I1ef3a3f10ed6ca5ec18d0af04b007fc3bc71a3cb
diff --git a/src/backends/backendsCommon/test/DynamicBackendTests.hpp b/src/backends/backendsCommon/test/DynamicBackendTests.hpp
index 561578e..4238ef6 100644
--- a/src/backends/backendsCommon/test/DynamicBackendTests.hpp
+++ b/src/backends/backendsCommon/test/DynamicBackendTests.hpp
@@ -1198,6 +1198,8 @@
     }
 }
 
+#if !defined(ARMNN_DYNAMIC_BACKEND_ENABLED)
+
 void RuntimeEmptyTestImpl()
 {
     using namespace armnn;
@@ -1218,6 +1220,8 @@
     BOOST_TEST(backendRegistry.Size() == 0);
 }
 
+#endif
+
 void RuntimeDynamicBackendsTestImpl()
 {
     using namespace armnn;