ED_area_newspace correctly changes an area's space when the type and
subtype are set beforehand. But SCREEN_OT_space_type_set_or_cycle, when
changing to a new editor rather than cycling, needs newspace to ignore
the set subtype and use the last-used saved in the space. This
situation cannot be tested for in newspace. Instead have the operator
pass -1 as subtype to signal this intended behavior.
Pull Request: https://projects.blender.org/blender/blender/pulls/135367
1a72a0f22c