Combine multiple `LIMIT`s

[ranma42]

It is currently possible to end up with multiple consecutive LIMIT in a query.
This is especially likely when combined with other query optimizations (such as those that drop unneeded ORDER BY), as mentioned in #34831

Removing them avoids nesting queries and in some cases makes it possible to use a simpler join instead of an apply.

[ahmednfwela]

I realize this has already been merged, but wouldn't it make sense to use the latest assigned limit, instead of calculating the least limit?

so q.Take(10).Take(90) should end up with Limit 90