Fortran: Fix asan problems with PDT testcases [PR121972]

Co-authored-by: Jerry DeLisle <jvdelisle@gcc.gnu.org>

	PR fortran/121972

gcc/fortran
	* expr.cc (has_parameterized_comps): Return false if the DT
	is neither a pdt_type nor has PDT components. Correct the
	logic for a PDT component.
	* trans-expr.cc (alloc_scalar_allocatable_for_assignment): Use
	calloc for types with paramterized components as well as those
	with allocatable components.
	* trans-stmt.cc (gfc_trans_allocate): Merge the allocation of
	parameterized components of PDTs and class PDTs into one block
	If an allocate type_spec is present that has allocatable comps
	where the class declared type does not, nullify the allocatable
	components.

gcc/testsuite/
	* gfortran.dg/asan/pdt_46.f03: Copy of original with tree dump
	for counts of frees, mallocs and callocs removed.
	* gfortran.dg/asan/pdt_77.f03: Ditto.
	* gfortran.dg/pdt_46.f03: Calloc count added, corresponding to
	reduction in mallocs..
	* gfortran.dg/pdt_50.f03: Ditto.