[clang] [serialization] no transitive decl change (PR #92083)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

I'd like to land this since:
- I want to give more time testing this
- the design of the patch is pretty similar with the previous one (https://github.com/llvm/llvm-project/pull/86912)
- the scale of the patch is not very big (100+ lines of code except new tests)
- I do think the functionality is very very important to modules.

https://github.com/llvm/llvm-project/pull/92083