[clang] [Clang][Modules] Fix generic lambda local capture mapping mismatch in template instantiation (PR #202248)

[Chuanqi Xu via cfe-commits]

https://github.com/ChuanqiXu9 commented:

Haven't looked into the details. But the description is not correct.

The attached test is not C++20 modules.

https://github.com/llvm/llvm-project/pull/202248