[flang] Use proper attributes for runtime calls with 'i1' arguments/returns.

Clang uses signext/zeroext attributes for integer arguments shorter than
the default 'int' type on a target. So Flang has to match this for functions
from Fortran runtime and also for BIND(C) routines. This patch implements
ABI adjustments only for Fortran runtime calls. BIND(C) part will be done
separately.

This resolves https://github.com/llvm/llvm-project/issues/58579

Differential Revision: https://reviews.llvm.org/D137050