ignore-tidy-linelength
This is step 2 towards fixing #77548. In the codegen and codegen-units test suites, the `//` comment markers were kept in order not to affect any source locations. This is because these tests cannot be automatically `--bless`ed.
This keeps FileCheck from tripping over unimportant differences in codegen.
Don't be so reliant on particular line ordering (though FileCheck makes this hard in general, IMO). Also disable for MSVC.
