Cox???s Executors v. Crockett & Co., 92 Va. 50, 58, 57, 22 S. E. 840, 843 (1895) (finding that suit by assignor following an adverse judgment against assignee was barred by res judicata but endorsing Pomeroy???s rule that an assignee could bring suit as the ???real party in interest??? even where the assignee must ???account to the assignor, or other person, for the residue, or even is to thus acc