The commit amends commit 3966b571 to take UNC prefix into account as
well. Fixes the weird file name output as reported in QTBUG-74291 and
QTBUG-83365. Replace manual separator normalizing in qt_cleanPath(),
this is another spot where UNC prefix handling needs to be applied.
Also make QTemporaryFile operate on '/' as file separators to fix
creating both file types with native path separators on network shares.
Fixes: QTBUG-74291
Fixes: QTBUG-76228
Fixes: QTBUG-83365
Pick-to: 5.15 6.0 6.1
Change-Id: Iff8d26b994bf4194c074cd5c996cda3934297fa5
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
ec9e856563