Fix route/test_route_consistency.py (#12512)

What is the motivation for this PR?
After announcing the routes, it is taking some time for kernel routes (IP-in-IP tunnel routes from standby ToR to active ToR) to be populated in ASIC_DB. And current sleep_interval is not enough for kernel routes to be populated in some of the runs and thus test is failing because of mismatch in pre_test_route_snapshot and post_test_route_snapshot (lead to AssertionError.

How did you do it?
Increased the sleep_interval (to ~100 secs) for time.sleep after announcing the routes (announce or withdraw) to give more time for kernel routes to be populated in ASIC_DB.

How did you verify/test it?
Test is consistently passing with the fix (verified on Arista-7260CX3-C64).

tests/route/test_route_consistency.py

@@ -43,10 +43,10 @@ def setup(self, duthosts):
         # take the snapshot of route table from all the DUTs
         self.__class__.pre_test_route_snapshot, max_prefix_cnt = self.get_route_prefix_snapshot_from_asicdb(duthosts)
         """sleep interval is calculated based on the max number of prefixes in the route table.
-           Addtional 60 seconds is added to the sleep interval to account for the time taken to
-           withdraw and advertise the routes by peers
+           Addtional 100 seconds is added to the sleep interval to account for the time taken to
+           withdraw and advertise the routes by peers.
         """
-        self.__class__.sleep_interval = math.ceil(max_prefix_cnt/3000) + 60
+        self.__class__.sleep_interval = math.ceil(max_prefix_cnt/3000) + 100
         logger.debug("max_no_of_prefix: {} sleep_interval: {}".format(max_prefix_cnt, self.sleep_interval))
 
     def test_route_withdraw_advertise(self, duthosts, tbinfo, localhost):