Fortran: Fix an excess finalization during allocation [PR104272]

Fortran: Fix an excess finalization during allocation [PR104272]

2023-04-14  Paul Thomas  <pault@gcc.gnu.org>

gcc/fortran
	PR fortran/104272
	* gfortran.h : Add expr3_not_explicit bit field to gfc_code.
	* resolve.cc (resolve_allocate_expr): Set bit field when the
	default initializer is applied to expr3.
	* trans-stmt.cc (gfc_trans_allocate): If expr3_not_explicit is
	set, do not deallocate expr3.

gcc/testsuite/
	PR fortran/104272
	* gfortran.dg/class_result_8.f90 : Number of builtin_frees down
	from 6 to 5 without memory leaks.
	* gfortran.dg/finalize_52.f90: New test