[integ-test-framework] Remove check on the number of os, scheduler, instances, regions when existing cluster is specified

When test_config YAML is specified, the meaning of the standalone arguments (--oss, --schedulers, --regions, --instances) are to filter the test, rather than running the test https://github.com/aws/aws-parallelcluster/blob/develop/tests/integration-tests/test_runner.py#L814. For example, we use ``--regions` in daily run to distinguish tests in develop.yaml across China, commercial, GovCloud

The check is wrong when using test_config YAML. Because we have been running test with test_config YAML, instead of fixing the check, this commit removes the check

Author: hanwen-cluster

tests/integration-tests/test_runner.py

@@ -845,15 +845,6 @@ def _get_config_arguments(args):
 
 
 def _check_args(args):
-    # If --cluster is set only one os, scheduler, instance type and region can be provided
-    if args.cluster:
-        if len(args.oss) > 1 or len(args.schedulers) > 1 or len(args.instances) > 1 or len(args.regions) > 1:
-            logger.error(
-                "when cluster option is specified, you can have a single value for oss, regions, instances "
-                "and schedulers and you need to make sure they match the cluster specific ones"
-            )
-            exit(1)
-
     if not args.tests_config:
         assert_that(args.regions).described_as("--regions cannot be empty").is_not_empty()
         assert_that(args.instances).described_as("--instances cannot be empty").is_not_empty()