[clang] [C++20] [Modules] Embed all source files for C++20 Modules (PR #102444)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

Thanks for the write-up. I've reverted and I'll try to open a RFC to get a wider discussion.

https://github.com/llvm/llvm-project/pull/102444