fix bound checks in crossmaplrn
fix bound checks in crossmaplrn

apaszke/cunn,andreaskoepf/cunn,apaszke/cunn,colesbury/cunn,colesbury/cunn,apaszke/cunn,jonathantompson/cunn,andreaskoepf/cunn,colesbury/cunn,jhjin/cunn,jhjin/cunn,jonathantompson/cunn