[clang] [clang] fix the unexpected control flow in ParseTentative.cpp (PR #109298)

[Nikita Popov via cfe-commits]

nikic wrote:

@cor3ntin See the discussion on https://github.com/llvm/llvm-project/pull/95917. This is very likely effectively dead code, but nobody is certain enough of that to delete it outright...

https://github.com/llvm/llvm-project/pull/109298