Using the same scale for the window as the
logical monitor only works correctly when having
the experimental 'scale-monitor-framebuffer'
feature enabled.
Without this experimental feature, the stream
will contain a black screen, where the actual
window only takes a small part of it.
Therefore, use a scale of 1 for the non-
experimental case.
Patch is based on commit 3fa6a92cc5dda6ab3939c3e982185f6caf453360.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/976
(cherry picked from commit e89cea8e5a9c944919cc0632b88bd68432778806)
9772f084bf