[clang] [Serialization] Load Specializations Lazily (1/2) (PR #76774)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

I failed to use spr to create stacked review... So I just create the stacked PR manually: https://github.com/llvm/llvm-project/pull/77417

https://github.com/llvm/llvm-project/pull/76774