[lldb][ObjC][NFC] Rewrite IsPossibleObjCMethodName in terms of llvm::StringRef#167660

Michael137 merged 1 commit intollvm:mainllvm/llvm-project:mainfrom

Michael137:lldb/objc-method-name-refactorMichael137/llvm-project:lldb/objc-method-name-refactorCopy head branch name to clipboard