minor test improvement: save temp copies of delta intermediate files with undefined behavior, so we can understand them better
minor test improvement: save temp copies of delta intermediate files with undefined behavior, so we can understand them better

DmitryOlshansky/dsmith,jacekburys/csmith,Panos90/csmith,natgla/csmith,jacekburys/csmith,Panos90/csmith,DmitryOlshansky/dsmith,jacekburys/csmith,jacekburys/csmith,natgla/csmith,DmitryOlshansky/dsmith,Panos90/csmith,natgla/csmith,natgla/csmith,jacekburys/csmith,DmitryOlshansky/dsmith,Panos90/csmith