[clang] [Clang][counted_by] Don't treat a __bdos argument as an array if it isn't (PR #125298)

[Bill Wendling via cfe-commits]

bwendling wrote:

@efriedma-quic Created https://github.com/llvm/llvm-project/pull/125571

https://github.com/llvm/llvm-project/pull/125298