Remove `Symbol.dispose` integration in `setTimeout` and `setInterval`

As part of the [Symbol.dispose] integration, the Timeout return type of setTimeout and setInterval support disposing (https://github.com/nodejs/node/pull/48633). This was stabilized last week (https://github.com/nodejs/node/pull/58467).

I think this integration should be removed, as the web platform setTimeout / setInterval do not support Symbol.dispose and never can, because it returns a number.

This means that folks may start writing new code that is incompatible between browser and Node, just because they use the Symbol.dispose integration here. That would be unfortunate.

It would also cause one more incompatibility between server side platforms with web setTimeout, and Node setTimeout (e.g Cloudflare Workers) (cc @jasnell).

@mcollina said in person that this was made stable recently enough to still remove it.

まず setTimeout と setInterval のエントリーポイント、および PR 48633 と 58467 にリンクされている変更を確認します。現在 Timeout がどのように Symbol.dispose を公開しているかを確認し、ブラウザータイマーに求められる互換性を特定します。この統合を削除しつつ、既存のタイマー動作を維持できれば完了です。