fix(ngAnimate): ensure that all jqLite elements are deconstructed properly

Prior to this fix if a form DOM element was fed into parts of the
ngAnimate queuing code it would attempt to detect if it is a jqLite
object in an unstable way which would allow a form element to return an
inner input element by index. This patch ensures that jqLite instances
are properly detected using a helper method.

Closes #11658