Don't update textarea defaultValue and input checked unnecessarily

[sebmarkbage]

In #26573 I changed it so that textareas get their defaultValue reset if you don't specify one.

However, the way that was implemented, it always set it for any update even if it hasn't changed.

We have a test for that, but that test only works if no properties update at all so that no update was scheduled. This fixes the test so that it updates some unrelated prop.

I also found a test for checked that needed a similar fix.

Interestingly, we don't do this deduping for defaultValue or defaultChecked on inputs and there's no test for that.

[react-sizebot]

Comparing: e5146cb...c6e4925

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name	+/-	Base	Current	+/- gzip	Base gzip	Current gzip
oss-stable/react-dom/cjs/react-dom.production.min.js	+0.01%	164.55 kB	164.58 kB	=	51.70 kB	51.69 kB
oss-experimental/react-dom/cjs/react-dom.production.min.js	+0.01%	166.13 kB	166.15 kB	+0.05%	52.17 kB	52.20 kB
facebook-www/ReactDOM-prod.classic.js	+0.01%	553.99 kB	554.05 kB	+0.01%	98.16 kB	98.17 kB
facebook-www/ReactDOM-prod.modern.js	+0.01%	537.83 kB	537.89 kB	+0.01%	95.49 kB	95.51 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against c6e4925

[sophiebits]

seems like if no value is specified, then we still set defaultValue on every rerender? that seems fine to me but then why care about the number of sets at all?

[sebmarkbage]

Yea, something is fishy. Maybe it doesn't rerender often in practice so it doesn't reset any selection state or something. I have a diff to avoid the diff in render which might surface that problem more frequently.

[sophiebits]

Setting .value to the same value isn't meant to affect the selection:

input: https://html.spec.whatwg.org/multipage/input.html#dom-input-value-value
textarea: https://html.spec.whatwg.org/multipage/form-elements.html#dom-textarea-value

defaultValue seems more ambiguous. (https://html.spec.whatwg.org/multipage/input.html#attr-input-value https://html.spec.whatwg.org/multipage/form-elements.html#dom-textarea-defaultvalue)