[flang] Handle lowering arguments in subroutine and function

This patch adds infrsatrcutrue to be able to lower
arguments in functions and subroutines.

This patch is part of the upstreaming effort from fir-dev branch.

Reviewed By: PeteSteinfeld

Differential Revision: https://reviews.llvm.org/D119957



Co-authored-by: Eric Schweitz <eschweitz@nvidia.com>
Co-authored-by: Jean Perier <jperier@nvidia.com>