mv: Set file flags after setting file times

[ricardobranco777]

Certain file flags prevent the setting of the file times, thus we should set the file times first.

This is done right in NetBSD: https://github.com/NetBSD/src/blob/trunk/bin/mv/mv.c#L327

In cp we also do the right thing: https://github.com/freebsd/freebsd-src/blob/main/bin/cp/utils.c#L300