Fortran: Fix ICE due to elemental procedure pointers [PR93924/5].

Fortran: Fix ICE due to elemental procedure pointers [PR93924/5].

2021-01-27  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/93924
	PR fortran/93925
	* trans-expr.c (gfc_conv_procedure_call): Suppress the call to
	gfc_conv_intrinsic_to_class for unlimited polymorphic procedure
	pointers.
	(gfc_trans_assignment_1): Similarly suppress class assignment
	for class valued procedure pointers.

gcc/testsuite/
	PR fortran/93924
	PR fortran/93925
	* gfortran.dg/proc_ptr_52.f90 : New test.

(cherry picked from commit 4225af228b5d52e8d7593dea49584c91b4bc2e1f)