[flang] Accept distinct kinds of arguments to IAND/IEOR/IOR (#69782)

As is already supported as a common extension for intrinsic functions
like DIM, allow distinct kinds of integer actual arguments to the
MIL-STD bit intrinsic functions IAND, IEOR, and IOR, with the kind of
the result being the largest of the kinds of the operands. (Though one
could make a case that IAND should return the smallest kind of its
operands, that's not what other compilers do.)