This should also fix an assert error if a -datadir with a trailing slash
is used on windows. This appears to be a real error and regression
introduced with #20744.
On windows (or at least wine), fs calls that actuallly access the
filesystem like fs::equivalent or fs::exists seem to treat directory
paths with trailing slashes as not existing, so it's necessary to
normalize these paths before using them. This fix adds a
path::lexically_normal() call to the failing assert so it passes.
80cd64e842