update ParallelLoop_tests to use _impl* interface
update ParallelLoop_tests to use _impl* interface

alexfrolov/grappa,buaasun/grappa,uwsampa/grappa,buaasun/grappa,alexfrolov/grappa,uwsampa/grappa,uwsampa/grappa,uwsampa/grappa,alexfrolov/grappa,buaasun/grappa,alexfrolov/grappa,uwsampa/grappa,uwsampa/grappa,buaasun/grappa,uwsampa/grappa,alexfrolov/grappa,alexfrolov/grappa,buaasun/grappa,alexfrolov/grappa,buaasun/grappa,buaasun/grappa