With Windows memory management tracking heap, it is important to use
it during the stream opening fallback. In Unix, the argument is
unused, but it is better to set it correctly.

* src/base/ftobjs.c (FT_Stream_New): Set memory before calling
`FT_Stream_Open`.
* builds/windows/ftsystem.c, builds/unix/ftsystem.c (FT_Stream_Open,
ft_close_stream_by_free): Call `ft_alloc` and `ft_free` with proper
memory argumment.