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

[Leandro Lupori via llvm-branch-commits]

luporl wrote:

This also broke the build of https://lab.llvm.org/buildbot/#/builders/141/builds/4432.

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