Fortran: Fix regression caused by r14-9752 [PR114959]

Fortran: Fix regression caused by r14-9752 [PR114959]

2024-04-29  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/114959
	* trans-expr.cc (gfc_trans_class_init_assign): Return NULL_TREE
	if the default initializer has all NULL fields. Guard this
	by a requirement that the code not be EXEC_INIT_ASSIGN and that
	the object be an INTENT_OUT dummy.
	* trans-stmt.cc (gfc_trans_allocate): Change the initializer
	code for allocate with mold to EXEC_ALLOCATE to allow an
	initializer with all NULL fields.

gcc/testsuite/
	PR fortran/114959
	* gfortran.dg/pr114959.f90: New test.