[clang] [llvm] [Serialization] Use stable hash functions (PR #96136)

[Chuanqi Xu via llvm-commits]

ChuanqiXu9 wrote:

> > This looks generally good.
> > > Some check-clang-modules tests still fail (@ChuanqiXu9)
> > 
> > 
> > What does this mean? Do you mean there are some failures after this patch? What are they? Or are these tests failing before this patch?
> 
> When https://github.com/MaskRay/llvm-project/tree/hashing-seed is applied, some module tests will fail. This PR fixes most of them but some are not and I am having a hard time figuring out them...
> 
> Applying this PR alone does not cause failures.

Which tests are still failing?

https://github.com/llvm/llvm-project/pull/96136