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/ClImportTensorHandleTests.cpp b/src/backends/cl/test/ClImportTensorHandleTests.cpp
index 931729a..6b1d352 100644
--- a/src/backends/cl/test/ClImportTensorHandleTests.cpp
+++ b/src/backends/cl/test/ClImportTensorHandleTests.cpp
@@ -61,7 +61,7 @@
     // Validate result by checking that the output has no negative values
     for(unsigned int i = 0; i < numElements; ++i)
     {
-        CHECK(typedPtr[i] >= 0);
+        CHECK(typedPtr[i] == 0);
     }
 }