Bug 1702670 - Fix state management for "last value change was interactive" for inputs / textareas. r=smaug

This and "value changed" affect the "too long" and "too short" validity
states.

The validity state tracking code is quite messy...

Differential Revision: https://phabricator.services.mozilla.com/D111254

dom/html/HTMLInputElement.h

@@ -200,7 +200,9 @@ class HTMLInputElement final : public TextControlElement,
 
   virtual EventStates IntrinsicState() const override;
 
- public:
+  void SetLastValueChangeWasInteractive(bool);
+  void ValueChangedOrLastValueChangeWasInteractiveChanged();
+
   // TextControlElement
   virtual nsresult SetValueChanged(bool aValueChanged) override;
   virtual bool IsSingleLineTextControl() const override;