[Serialization] Migrate away from PointerUnion::get (NFC)#120844

kazutakahirata merged 1 commit intollvm:mainllvm/llvm-project:mainfrom

kazutakahirata:cleanup_001_PointerUnion_clang_MultiOnDiskHashTablekazutakahirata/llvm-project:cleanup_001_PointerUnion_clang_MultiOnDiskHashTableCopy head branch name to clipboard