KDevelop cpp file causes DoS on CI nodes

Hi Milian,

This morning I noticed that 2/3 of our Windows CI nodes were offline, due
to them being killed by the OOM killer.

Investigation has traced it back to cppcheck, which appears to have serious
problems with the following file currently on a work branch you're working
on, with cppcheck using far in excess of 8GB of RAM when trying to process
that file (see https://invent.kde.org/kdevelop/kdevelop/-/jobs/722348)

The file in question is
https://invent.kde.org/kdevelop/kdevelop/-/blob/work/kdev-clang-cache-types/plugins/clang/tests/files/kdev_ignored/mangle-ms-back-references-pr13207.cpp

Can we please get it removed from the repository or otherwise fixed to not
trigger this cppcheck bug?
Please do not test any fixes for this issue on the CI system - as it will
cause the Windows (and even potentially FreeBSD) CI worker nodes to be
killed.

Thanks,
Ben