Fortran: Regression- fix ICE at fortran/trans-decl.c:1575 [PR96087]

2025-01-23  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/96087
	* trans-decl.cc (gfc_get_symbol_decl): If a dummy is missing a
	backend decl, it is likely that it has come from a module proc
	interface. Look for the formal symbol by name in the containing
	proc and use its backend decl.
	* trans-expr.cc (gfc_apply_interface_mapping_to_expr): For the
	same reason, match the name, rather than the symbol address to
	perform the mapping.

gcc/testsuite/
	PR fortran/96087
	* gfortran.dg/pr96087.f90: New test.