[clang] [clang-tools-extra] [llvm] [clang][modules] Serialize `CodeGenOptions` (PR #146422)

[Jan Svoboda via llvm-commits]

jansvoboda11 wrote:

I rebased this PR on top of https://github.com/llvm/llvm-project/pull/146766 and https://github.com/llvm/llvm-project/pull/146910. PTAL

https://github.com/llvm/llvm-project/pull/146422