Adds CustomAllocator interface and Sample App

 * Updates the runtime options with a CustomAllocatorMap which allows to define a CustomAllocator for specific backends
 * Change IBackendInternal interface to use a shared pointer to a custom allocator
 * Update ClBackend.hpp/cpp to use the CustomAllocator
 * Adds an example application and unit test which uses a CustomAllocator for GpuAcc
 * Refactor of the interface to use MemorySource instead of the user Mapping cl_mem directly
 * Modify the BackendRegistry to also hold a registry of CustomAllocators
 * BackendRegistry Deregister will also deregister any allocators associated with that backend id
 * set_global_allocator within the BaseMemoryManager so that it always matches the currently used allocator

Signed-off-by: Jan Eilers <jan.eilers@arm.com>
Change-Id: I156d819686021865f4375e6cb7a5c5dec8fee9e8
Signed-off-by: David Monahan <david.monahan@arm.com>
diff --git a/src/backends/cl/test/CMakeLists.txt b/src/backends/cl/test/CMakeLists.txt
index 6662a1e..41cbe24 100644
--- a/src/backends/cl/test/CMakeLists.txt
+++ b/src/backends/cl/test/CMakeLists.txt
@@ -6,6 +6,7 @@
 list(APPEND armnnClBackendUnitTests_sources
     ClContextControlFixture.hpp
     ClContextSerializerTests.cpp
+    ClCustomAllocatorTests.cpp
     ClCreateWorkloadTests.cpp
     ClEndToEndTests.cpp
     ClImportTensorHandleFactoryTests.cpp