Setting `$state` with `NaN` causes updates

[trueadm]

Describe the problem

When setting state with NaN it causes an update even though NaN is the same value as before.

<script>
	let x = $state(NaN);
</script>

<button onclick={() => {
	x = NaN
}}>Set NaN</button>

{#key x}
	<iframe title="Svelte" src="https://svelte.dev"></iframe>
{/key}

Playground

Describe the proposed solution

Svelte should either switch to using Object.is for default equality or it should provide a way of supplying a custom equals function.

Importance

would make my life easier

[dummdidumm]

Closing as duplicate of #10061