The introduction of TestSuiteSpec adds auto-discovery of test suites,
which are also automatically imported. This causes double imports as the
runner loads the test suites. This changes the behaviour of the runner
to load the imported classes from TestSuiteSpec instead of importing
them again.

Signed-off-by: Luca Vizzarro <luca.vizzarro@arm.com>
Reviewed-by: Paul Szczepanek <paul.szczepanek@arm.com>

+            filtered_test_cases: list[TestCase] = [
+                test_case
+                for test_case in test_suite_spec.test_cases
+                if not test_suite_config.test_cases_names
+                or test_case.name in test_suite_config.test_cases_names
+            ]