re PR fortran/50981 ([OOP] Wrong-code for scalarizing ELEMENTAL call with absent OPTIONAL argument)

fortran/
	PR fortran/50981
	* gfortran.h (gfc_is_class_container_ref): New prototype.
	* class.c (gfc_is_class_container_ref): New function.
	* trans-expr.c (gfc_conv_procedure_call): Add a "_data" component
	reference to polymorphic actual arguments.

testsuite/
	PR fortran/50981
	* gfortran.dg/elemental_optional_args_5.f03: Add subcomponent actual
	argument checks.

From-SVN: r184904