[clang] [Modules] Delay deserialization of preferred_name attribute at r… (PR #122726)

[Ben Langmuir via cfe-commits]

benlangmuir wrote:

There's probably a better way, but I just built my first clang normally then built a second one with
`-DCMAKE_C_COMPILER` and `-DCMAKE_CXX_COMPILER` pointing to the first one, and `-DLLVM_ENABLE_MODULES=1` to enable modules.

https://github.com/llvm/llvm-project/pull/122726