COMPMID-1007: Add initial validate support to backend

Change-Id: I55eae35f35a3c7891e8d535907c861f022e43bea
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/125470
Tested-by: Jenkins <bsgcomp@arm.com>
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
diff --git a/arm_compute/graph2/detail/ExecutionHelpers.h b/arm_compute/graph2/detail/ExecutionHelpers.h
index acd1654..e4523ec 100644
--- a/arm_compute/graph2/detail/ExecutionHelpers.h
+++ b/arm_compute/graph2/detail/ExecutionHelpers.h
@@ -50,6 +50,11 @@
  * @param[in] g Graph to allocate the tensors
  */
 void allocate_all_tensors(Graph &g);
+/** Validates all nodes
+ *
+ * @param[in] g Graph to validate
+ */
+void validate_all_nodes(Graph &g);
 /** Configures all nodes of graph
  *
  * @param[in] g   Graph to configure the nodes