Move where the user-valid/invalid flag is set.

[emilio]

Fixes #10066, matches at least WebKit and (soon) Gecko.

Also renames the flag to just "user valid or invalid flag", since that's what it is and it has nothing to do with user interaction.

• At least two implementers are interested (and none opposed):
  • WebKit (this precisely matches their behavior).
  • Gecko
• Tests are written and can be reviewed and commented upon at:
  • Without this change, existing user-valid/invalid tests don't pass.
• Implementation bugs are filed:
  • Chromium: N/A (matches this I think)
  • Gecko: https://bugzilla.mozilla.org/show_bug.cgi?id=1850295
  • WebKit: N/A
• MDN issue is filed: Not needed I think
• The top of this comment includes a clear commit message to use.

(See WHATWG Working Mode: Changes for more details.)

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/form-control-infrastructure.html ( diff )
/form-elements.html ( diff )
/input.html ( diff )
/interaction.html ( diff )
/semantics-other.html ( diff )

[annevk]

Mainly editorial nits. I hope @nt1m and @josepharhar can review substance.

[nt1m]

Looks good to me.