Complexity of algorithm to test if a graph is asymmetric
The complement of your problem is known as graph automorphism problem (GA). It is a candidate for $NP$-intermediate problems. The problem is not known to be solvable in polynomial time. Also, It is not known to be $NP$-complete. It polynomialy reduces to the graph isomorphism problem (GI) but no known polynomial reduction from GI to GA. Unique-GI is equivalent to GA.