Before: make -sr UITest_calc_tests -> 10m48.934s
After: make -sr -j4 UITest_calc_tests UITest_calc_tests2 UITest_calc_tests3 UITest_calc_tests4 -> 5m40.113s
As a start just split based on the number of .py files in the
directories, one could improve this further by making them even more
equal based on number of lines or something.
Tested-by: Jenkins <firstname.lastname@example.org>
Reviewed-by: Miklos Vajna <email@example.com>