Prevent potential memory leaks in jQueryUI pseudo selectors

When these pseudo selectors are used, they have the side effect of creating the data cache for a given element somewhat surprisingly.  If you use these pseudo selectors on a set of elements and then null out those references ( or just let them fall out of scope ) without first calling something that invokes `$.cleanData`, you've just leaked memory.

I could not figure out a way to reasonably unit test this since in jQuery 2.x, there is no way to actually inspect whether or not the cache exists for a given element since it's contained entirely within jQuery's closure.

Fixes #10538