[clang] [RFC] Initial implementation of P2719 (PR #113510)

[via cfe-commits]

zmodem wrote:

> Could anyone with a windows machine see if you can work out what is happening with the windows test failure? I don't understand why the tests are failing on the windows bot as it seems like it should simply fail everything (e.g. windows driver is going wrong) or it should work

It looks like the latest commit did pass on Windows, so this may be redundant but it also passes locally on my Windows machine.

https://github.com/llvm/llvm-project/pull/113510