Tests could be now run from any dir.

it was e.g.:

	lsblk: /dev/md: not a block device
	lsblk: /dev/md: not a block device
	# md:   rev

now:

	# md1 (raid0) -> sda3  sdb3
	# sda: SAMSUNG MZ7LN256  rev 100Q 238.5G
	# sdb: SAMSUNG MZ7LN256  rev 100Q 238.5G

The problem with `getent hosts ...` is that /etc/hosts has to be
manually prepared for it to work and it just does not scale and is error
prone.

So just extract machine global IP addresses at runtime as configured on
the interfaces.

neotest part pending.

compared to tgro5:

tgro0   py -> noise (ZEO, NEO/pylite, NEO/pysql, partly neo/go)
tgro10  py=no-noise, tpy~=tgro5; tgo serial~same, +prefetch more noise (?) 40|65
tgro15  lat_tcp 1B 49->45 sometime (consistently) otherwise more-or-less same
tgro20  lat_tcp 4K 170µs->167µs (c)
tgro25  lat_tcp 4K 170µs->167µs (c), lat_tcp 4K 175 -> 171µs (go)
        ZEOv a bit
        go-go + prefetch !sha1 -> noise + higher (~65µs -> 70 - 110µs)

txc40µs4f seems to be worse than txc200µs4f