`window` is injected as an `object` in webworker scripts instead of `undefined`

### Link to the code that reproduces this issue https://codesandbox.io/p/devbox/boring-hill-2w8x38?file=%2Fapp%2Fworker.ts%3A5%2C44 ### To Reproduce 1. Start the application in dev 2. Click the "Send to worker" button 3. Inspect the console ### Current vs. Expected behavior Until next@14.0.5-canary.20, `typeof window` returned `undefined` inside a webworker as expected. However since next@14.0.5-canary.20, `typeof window` returns `object` but this object cannot be accessed. Therefore, as it stands, third party libraries making use of `window` via an `undefined` test cannot work anymore in webworkers in Nextjs. The most notable example if **Three.js** which includes this snippet at the end of the library - ```js if ( typeof window !== 'undefined' ) { if ( window.__THREE__ ) { console.warn( 'WARNING: Multiple instances of Three.js being imported.' ); } else { window.__THREE__ = REVISION; } } ``` ### Provide environment information ```bash All ``` ### Which area(s) are affected? (Select all that apply) SWC transpilation ### Which stage(s) are affected? (Select all that apply) next dev (local), next build (local), next start (local), Other (Deployed) ### Additional context This bug was first introduced in next@14.0.5-canary.20