TC-DA-1.4/8 generation script: use standard order (project-chip#29920)

listdir doesn't use any particular ordering apparently, so this
comes out in a different order every time, which is very annoying.

Change to use sorted. I'm going to update the test plans to use
the new ordering so it doesn't keep changing and so we can match
it with the runner script.

credentials/development/gen_commissioner_dut_test_plan_table.py

@@ -79,7 +79,7 @@ def main():
 
     success_cases = []
     failure_cases = []
-    for p in os.listdir(cert_path):
+    for p in sorted(os.listdir(cert_path)):
         if p in skip_cases:
             continue
         path = str(os.path.join(cert_path, p, 'test_case_vector.json'))