Revert "Fix #13291, no longer need the functionish-regex guard."

Turns out this is still needed by Safari 5.1, which we're still supporting.

This reverts commit c4b1da40075532e4f14821b1519ae0ef6665bf1e.
Fix comment about Safari shortfalls.
Fix #13349. No need to sort simple .find() cases.
Minor updates. All parameters of an internal function are for internal use only.
Revert change to visible/hidden selectors until 1.10 and 2.1. Reopens #13132, #10406.
Magic fixing for previous commit