Fast path opportunity in `checkVariableLikeDeclaration`

I noticed that for this code:

class A {
  state = { foo: "foo", bar: 42 };
}

checkVariableLikeDeclaration calls checkTypeAssignableToAndOptionallyElaborate here:
https://github.dev/microsoft/TypeScript/blob/e9868e96e87996df46a13b4323866acc639e71ce/src/compiler/checker.ts#L40690

This is likely redundant for cases without a declared type as it's guaranteed that this has to return true. I thought at first that this would rely on a fast past based on the type.id but it seems that those types have different ids (perhaps one is fresh while the other one isn't or something?).

I'm happy to explore this optimization. But perhaps you'd have some preferences as to at which level this should be applied?

cc @jakebailey

Inizia in src/compiler/checker.ts, in checkVariableLikeDeclaration e nella sua chiamata a checkTypeAssignableToAndOptionallyElaborate. Usa l’esempio del campo di classe nell’issue per verificare se il controllo è ridondante quando non è presente alcun tipo dichiarato e se i diversi type IDs sono rilevanti. Conferma il comportamento dell’ottimizzazione e misura se migliora questo percorso.