[clang] [clang-repl] Fix error recovery while PTU cleanup (PR #127467)

[David Spickett via cfe-commits]

DavidSpickett wrote:

Also failing on Windows x64, but this time the error is better:
https://lab.llvm.org/buildbot/#/builders/63/builds/7023

And now I see the actual problem, all I had to do was scroll up :)
```
# .---command stderr------------
# | In file included from <<< inputs >>>:1:
# | input_line_22:1:17: error: non-local lambda expression cannot have a capture-default
# |     1 | auto capture = [&]() { return x * 2; };
# |       |                 ^
# | error: Parsing failed.
# `-----------------------------
```

Puzzling that we don't see this on other platforms though.

https://github.com/llvm/llvm-project/pull/127467