[flang] Do not move finalized function results in lowering (#80683)

Fortran requires finalizing function results when the result type have
final procedures.

Lowering was unconditionally "moving" function results into values
"hlfir.expr". This is not correct when the results are finalized because
it means the function result storage will be used after the hlfir.expr.

Only move function results that are not finalized.