[sonic-mgmt] Fix "dualtor/test_orchagent_standby_tor_downstream.py"

Fixes include:
1) Make log_analyzer to ignore "SAI_API_TUNNEL:_brcm_sai_mptnl_*" log messages,
   similar to other tests done as part of PR#14199.
2) Increase wait time for expected route to be populated after bgp
   restart.

tests/dualtor/test_orchagent_standby_tor_downstream.py

@@ -41,6 +41,23 @@
 logger = logging.getLogger(__file__)
 
 
+@pytest.fixture(autouse=True)
+def ignore_expected_loganalyzer_exception(loganalyzer, duthosts):
+
+    ignore_errors = [
+        r".* ERR syncd#syncd: .*SAI_API_TUNNEL:_brcm_sai_mptnl_tnl_route_event_add:\d+ ecmp table entry lookup "
+        "failed with error.*",
+        r".* ERR syncd#syncd: .*SAI_API_TUNNEL:_brcm_sai_mptnl_process_route_add_mode_default_and_host:\d+ "
+        "_brcm_sai_mptnl_tnl_route_event_add failed with error.*"
+    ]
+
+    if loganalyzer:
+        for duthost in duthosts:
+            loganalyzer[duthost.hostname].ignore_regex.extend(ignore_errors)
+
+    return None
+
+
 @pytest.fixture(params=['ipv4', 'ipv6'])
 def ip_version(request):
     """Traffic IP version to test."""
@@ -262,7 +279,7 @@ def test_standby_tor_downstream_loopback_route_readded(
         rand_unselected_dut.shell("config bgp start all")
     pt_assert(
         wait_until(
-            10, 1, 0,
+            60, 1, 0,
             lambda: route_matches_expected_state(rand_selected_dut, active_tor_loopback0, expect_route=True)),
         "Expected route {} not found on {}".format(active_tor_loopback0, rand_selected_dut)
     )