Despite its name, it did the same thing as
TestCloneNEWUSERAndRemapRootDisableSetgroups in old code. So fix it.

Change-Id: I21265e539179c51980e16f07a553a9bf5bb7903f
Reviewed-on: https://go-review.googlesource.com/35273
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>