Fortran: Fix ICE in interface mapping with assumed rank [PR102619]

2026-03-27  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/102619
	* trans-expr.cc (gfc_get_interface_mapping_array): Add argument
	'assumed_rank_formal', which if true returns the descriptor in
	'ifm'.
	(gfc_add_interface_mapping): Detect an assumed rank formal arg
	of a non-intrinsic function to set 'assumed_rank_formal' and
	pass the descriptor to gfc_get_interface_mapping_array.

gcc/testsuite/
	PR fortran/102619
	* gfortran.dg/pr102619.f90: New test.