D52774 fixed a bug with typo correction of includes, but didn't add
a test.
D65907 then broke recovery of typo correction of includes again,
because it extracted the code that writes to Filename to a separate
function that took the parameter not by reference.
Fix that, and also don't repeat the slash normalization computation
and fix both lookup and regular file name after recovery.
Differential Revision: https://reviews.llvm.org/D79595
See PR45812 for motivation.
No explicit test since I couldn't figure out how to get the
current disk drive in lower case into a form in lit where I could
mkdir it and cd to it. But the change does have test coverage in
that I can remove the case normalization in lit, and tests failed
on several bots (and for me locally if in a pwd with a lower-case
drive) without that normalization prior to this change.
Differential Revision: https://reviews.llvm.org/D79531
Nico Weber