IMPALA-8499: avoid datetime.total_seconds() in test_insert_events

This function was only added in Python 2.7.

Change-Id: I8e6e556d99d07c1f559a2097fbd634bfc5eaaa52
Reviewed-on: http://gerrit.cloudera.org:8080/13245
Reviewed-by: Todd Lipcon <todd@apache.org>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Reviewed-on: https://gerrit.sjc.cloudera.com/c/cdh/impala/+/49695
CDH-Build: Vihang Karajgaonkar <vihang@cloudera.com>
Reviewed-by: Vihang Karajgaonkar <vihang@cloudera.com>
Quasar-L0: Vihang Karajgaonkar <vihang@cloudera.com>
Tested-by: Vihang Karajgaonkar <vihang@cloudera.com>

tests/custom_cluster/test_event_processing.py

@@ -18,7 +18,6 @@
 import pytest
 import json
 import time
-from datetime import datetime
 from tests.common.environ import build_flavor_timeout
 import requests
 from tests.common.skip import SkipIfS3, SkipIfABFS, SkipIfADLS, SkipIfIsilon, SkipIfLocal
@@ -110,11 +109,11 @@ def wait_for_insert_event_processing(self, previous_event_id):
     """
     new_event_id = self.get_last_synced_event_id()
     success = True
-    start_time = datetime.now()
+    start_time = time.time()
     while new_event_id - previous_event_id < 2:
       new_event_id = self.get_last_synced_event_id()
       # Prevent infinite loop
-      time_delta = (datetime.now() - start_time).total_seconds()
+      time_delta = time.time() - start_time
       if time_delta > 10:
         success = False
         break