Merge topic 'realpath-windows'

16af27fd42 cmSystemTools: Drop GetRealPathResolvingWindowsSubst
823e1df54c cmSystemTools: Implement GetRealPath on Windows

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !9973