Script for random algorithm selection in system tests

Script for random algorithm selection in system tests

Multiple algorithm sets can be defined in this script. These can be
selected via the ALGORITHM_SET environment variable. For compatibility
reasons, "stable" set contains the currently used algorithms, since our
system tests need some changes before being compatible with randomly
selected algorithms.

The script operation is similar to the get_ports.py - environment
variables are created and then printed out as `export NAME=VALUE`
commands, to be interpreted by shell. Once we support pytest runner for
system tests, this should be a fixture instead.

(cherry picked from commit 5f480c8485261f32b0e9b15630cebed0e8d80eaa)