Make more use of fpc_*_array (mainly fpc_addref_array) in rtl/inc/dynarr.inc.
Since rtl/inc/dynarr.inc already uses fpc_initialize_array (as int_InitializeArray) and fpc_finalize_array (as int_FinalizeArray) without a second thought (proving the impossibility of a hypothetical case where element size from the array type info <> element size from the element type info), fpc_addref_array should also be fine. (Was going to add it to !383 (closed) but it looks too good for that...)