[llvm-branch-commits] [clang] [Serialization] Code cleanups and polish 83233 (PR #83237)

[Vassil Vassilev via llvm-branch-commits]

vgvassilev wrote:

> @ilya-biryukov hi, the functional and performance test on the root side looks good: [root-project/root#14495 (comment)](https://github.com/root-project/root/pull/14495#issuecomment-1980589145)
> 
> Could you try to test this within google internals?
> 
> Also if your projects implements new ExternalASTSource, you need to handle that like I did in root: [ChuanqiXu9/root at 570fd78](https://github.com/ChuanqiXu9/root/commit/570fd783875671d346c7cdc0d98a8a9afcad05a4)

@ilya-biryukov, can you test this PR on your side. We'd like to move forward.

cc: @dwblaikie 

https://github.com/llvm/llvm-project/pull/83237