Test that the DHCPv4 lease got renewed after the T1 timer runs out.
Then also simulate the DHCPREQUEST during renew being lost and
retransmitted and the lease eventually getting renewed T1 + 60s later.
The main downside is that this test will inevitably take a while if
running in Qemu without the time travel ability.
Update the test and some utility code to run hostapd in an isolated net
namespace for connection_test.py. We now need a second hostapd
instance though because in static_test.py we test ACD and we need to
produce an IP conflict. Moving the hostapd instance unexpectedly fixes
dhcpd's internal mechanism to avoid IP conflicts and it would no longer
assign 192.168.1.10 to the second client, it'd notice that address was
already in use and assign the next free address, or fail if there was
none. So add a second hostapd instance that runs in the main namespace
together with the statically-configured client, it turns out the test
relies on the kernel being unable to deliver IP traffic to interfaces on
the same system.
