zdtm.py: Run tests in best flavor

If someone wants to run all tests in any, but the most
difficult for criu, flavor, the 'best' one is introduced.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Ruslan Kuprieiev <rkuprieiev@cloudlinux.com>

test/zdtm.py

@@ -970,7 +970,10 @@ def run_tests(opts):
 
 			test_flavs = tdesc.get('flavor', 'h ns uns').split()
 			opts_flavs = (opts['flavor'] or 'h,ns,uns').split(',')
+			if opts_flavs != ['best']:
 				run_flavs = set(test_flavs) & set(opts_flavs)
+			else:
+				run_flavs = set([test_flavs.pop()])
 
 			if run_flavs:
 				l.run_test(t, tdesc, run_flavs)