And, use by default, the single background surface. This keeps the
multiple surfaces on CI, to at least have some code that stress that
code in the compositor.
Bug-AGL: SPEC-4712 Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Change-Id: I8f9ef17e39e829eff08c3608e405e1d9f85575d4