test: use an origin test name to generate uniq name for test files

Currently ns/test and test may have the same test directory,
especially if zdtm.sh is executed with --ct.

Reported-by: Mr Jenkins
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
test: clean up pages immediately after restore

We see big load-avarage for the CRIU-iter job, because the host is
writing images for the maps04 test. If we will remove images after retore,
they will live in a page cache. Curretly we collect images for three
iterations and their size is too big to live in a cache.

[root@jenkins workspace]# time bash test/zdtm.sh  -i 3 ns/static/maps04
real	2m23.765s
user	0m0.719s
sys	0m4.006s
[root@jenkins workspace]# time bash test/zdtm.sh -C -i 3 ns/static/maps04
real	1m34.884s
user	0m0.200s
sys	0m4.191s

Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>