fix: $state.is missing second argument on the server

[paoloricciuti]

Svelte 5 rewrite

Closes #11829

On the server the transform was missing the second argument so the generated code was from $state.is(a, b) to Object.is(a) resulting in always false.

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[Conduitry]

I believe we have some other tests that are specifically testing SSR-only behavior without hydration. We should be able to do something that makes assertions about the behavior of the component rather than testing for specific compiler output - which is brittle, and makes it difficult to see what behavior is actually being tested for. Snapshot testing should be reserved for when there really isn't another good way to test what we're looking for via the component's externally visible behavior.

[paoloricciuti]

I believe we have some other tests that are specifically testing SSR-only behavior without hydration. We should be able to do something that makes assertions about the behavior of the component rather than testing for specific compiler output - which is brittle, and makes it difficult to see what behavior is actually being tested for. Snapshot testing should be reserved for when there really isn't another good way to test what we're looking for via the component's externally visible behavior.

Uhm yeah i guess i can just test the result of object.is SSRd...i tought that since this was specifically about the code output was better to test through snapshot. Fixing now.