I got sidetracked apparently and never finished writing this Clone
code in 316afe7d02babc (#17448). (It really should use views instead.)
And then I missed one of the users of "routerChanged" that was broken up
into "routerChanged" vs "dnsChanged".
This broke integration tests elsewhere.
Fixes#17506
Change-Id: I533bf0fcf3da9ac6eb4a6cdef03b8df2c1fb4c8e
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>