fix `link.renameTmpIntoCache` on windows when dest dir exists.
Previously it would fail as `renameW` do not ever fail with
`PathAlreadyExists`.
As a workaround we check for dest dir existence before rename
on Windows.
b9d86c6bc8jagt committed on 4/12/2022, 10:01:25 AM· committed by Andrew Kelleyparentc4aac28