* nsfns.m: Declare image_cache_refcount if GLYPH_DEBUG.

* nsfns.m: Declare image_cache_refcount if GLYPH_DEBUG.
(unwind_create_frame): New function.
(Fx_create_frame): Restructure code to be more similar to the one in
xfns.c.  Call record_unwind_protect with unwind_create_frame (Bug#9943).
Initialize image_cache_refcount if GLYPH_DEBUG (Bug#9943).
Move terminal->reference_count++ just before making the frame official
(Bug#9943).

* nsterm.m (x_free_frame_resources): New function.
(x_destroy_window): Move code to x_free_frame_resources.