TypeScript 6 API Bug - `isSourceFileDefaultLibrary` false negative on program structure reuse

[StyleShit]

🔎 Search Terms

isSourceFileDefaultLibrary

🕗 Version & Regression Information

• This changed between versions 5.9.3 and 6.0.0-beta
• This changed in commit or PR - Remove no-default-lib #62435

⏯ Playground Link

No response

💻 Code

https://github.com/StyleShit/repros/tree/main/ts-6-isSourceFileDefaultLibrary

🙁 Actual behavior

isSourceFileDefaultLibrary returns false for source files in the default library

🙂 Expected behavior

isSourceFileDefaultLibrary will return true for source files in the default library, as in previous versions

Additional information about the issue

I'm willing to send a PR to fix this