short-circuit filter for dbDelta

[m_uysl]

dbDelta function can cause strange things on the large-scale WordPress installations. When you have large amounts of data, you don't really want to schema changes apply directly on the production. (at least we don't do that)

So, I recommend adding new short-circuit filter to avoid that.

(I know, returning an empty array with dbdelta_queries might be a workaround but not ideal for this job.)