[PSM Interop] URL Map graceful teardown (#33090)

Similar to what we already do in other test suites:

- Try cleaning up resources three times.
- If unsuccessful, don't fail the test and just log the error. The
cleanup script should be the one to deal with this.

ref b/282081851

tools/run_tests/xds_k8s_test_driver/framework/xds_url_map_testcase.py

@@ -57,6 +57,7 @@ GcpResourceManager = xds_url_map_test_resources.GcpResourceManager
 HostRule = xds_url_map_test_resources.HostRule
 PathMatcher = xds_url_map_test_resources.PathMatcher
 JsonType = Any
+_timedelta = datetime.timedelta
 
 # ProtoBuf translatable RpcType enums
 RpcTypeUnaryCall = 'UNARY_CALL'
@@ -362,11 +363,26 @@ class XdsUrlMapTestCase(absltest.TestCase, metaclass=_MetaXdsUrlMapTestCase):
 
     @classmethod
     def cleanupAfterTests(cls):
-        logging.info('----- Doing cleanup after %s -----', cls.__name__)
-        cls.test_client_runner.cleanup(force=True, force_namespace=True)
+        logging.info('----- TestCase %s teardown -----', cls.__name__)
+        retryer = retryers.constant_retryer(wait_fixed=_timedelta(seconds=10),
+                                            attempts=3,
+                                            log_level=logging.INFO)
         cls.finished_test_cases.add(cls.__name__)
-        if cls.finished_test_cases == cls.test_case_names:
-            # Tear down the GCP resource after all tests finished
+        # Whether to clean up shared pre-provisioned infrastructure too.
+        # We only do it after all tests are finished.
+        cleanup_all = cls.finished_test_cases == cls.test_case_names
+
+        # Graceful cleanup: try three times, and don't fail the test on
+        # a cleanup failure.
+        try:
+            retryer(cls._cleanup, cleanup_all)
+        except retryers.RetryError:
+            logging.exception('Got error during teardown')
+
+    @classmethod
+    def _cleanup(cls, cleanup_all: bool = False):
+        cls.test_client_runner.cleanup(force=True, force_namespace=True)
+        if cleanup_all:
             GcpResourceManager().cleanup()
 
     def _fetch_and_check_xds_config(self):