add system-tests-3 tenant to suites.yaml
add system-tests-3 tenant to suites.yaml

isaac-s/cloudify-system-tests,isaac-s/cloudify-system-tests,isaac-s/cloudify-system-tests,codilime/cloudify-system-tests,cloudify-cosmo/cloudify-system-tests,codilime/cloudify-system-tests,codilime/cloudify-system-tests,cloudify-cosmo/cloudify-system-tests