[AST] Migrate away from PointerUnion::get (NFC)#119949

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

kazutakahirata:cleanup_001_PointerUnion_clang_ASTkazutakahirata/llvm-project:cleanup_001_PointerUnion_clang_ASTCopy head branch name to clipboard