Fix rewrite_reduce pass when running SD3 mmdit

[kahmed10]

Used this workaround to get mmdit working, but there seems to be a bug with the find_reduce_mean_variance{} matcher.

void rewrite_reduce::apply(module& m) const
{
    match::find_matches(m, find_softmax{});
    // match::find_matches(m, find_reduce_mean_variance{});
    match::find_matches(m, find_reduce_mean{});
}