Bug 1597679 - part 2: Make `nsITextControlElement` inherit `nsGenericHTMLFormElementWithState` r=smaug

Sub classes of `nsITextControlElement` are only `HTMLInputElement` and
`HTMLTextAreaElement`. And both base class is
`nsGenericHTMLFormElementWithState`.  Therefore, we can make
`nsITextControlElement` inherit `nsGenericHTMLFormElementWithState` and
make `HTMLInputElement` and `HTMLTextAreaElement` inherit
`nsITextControlElement`.  Then, we can get rid of a lot of QI between
`nsINode`/`nsIContent`/`Element` and `nsITextControlElement` (and note that
some of them in a hot path).

Additionally, this patch renames `nsITextControlElement` to
`mozilla::TextControlElement`.

Differential Revision: https://phabricator.services.mozilla.com/D54330

--HG--
rename : dom/html/nsITextControlElement.h => dom/html/TextControlElement.h
extra : moz-landing-system : lando