meson: skip the fallback for sysprof on Windows

Otherwise it will download the subproject and fail when trying to build
it since sysprof is Linux only.

Instead skip the fallback on Windows, so that if force-enabled it will
fail, but in auto mode it will just skip sysprof.


(cherry picked from commit 01e361fcb9a4775e98ce13bc7f0c56ac405e9d3a)