Selector: Fix test iframe submission for firefox

Ref jquery/sizzle@20fbadb0870bd30e0e66c68891f121c0450374c4
(Cherry-picked from efc4f8d7814a8c44bd5b4d924d237a04263e1a85)
Selector: Use jQuery reference not Sizzle

(Cherry-picked from 3b9057a18de31b838bd0dd25ea466993b62f9dd9)
Ajax: move ajax event aliases to their own file

Fixes #15126