Stats: Revert back to limiting ops?

[emrikol]

Prior to 3.2.0 we limited the number of ops shown to 500. I believe it would still be good to have a soft limit like this. When debugging sites with caching issues, that are doing tens or hundreds of thousands of ops per transaction, this can cause the browser to lock up trying to load and parse all of the data.

Now, it's obvious that the site is _doing_it_wrong() but having the ability to use Debug Bar to help debug the issue and related issues would be really helpful.