xds: Add xds dependency to the fallback test client (#5062)
xds: Add xds dependency to the fallback test client (#5062)


menghanl/grpc-go,dfawley/grpc-go,grpc/grpc-go,dfawley/grpc-go,menghanl/grpc-go,grpc/grpc-go,stanley-cheung/grpc-go,stanley-cheung/grpc-go