[advanced-reboot][dualtor] Update Loopback0 ping test: expect same count for sent and rcvd packets (#9599) (#10068)

Raising PR for cherry-pick conflict:
225e257 [advanced-reboot][dualtor] Update Loopback0 ping test: expect same count for sent and rcvd packets (#9599)

Summary: Currently dual tor warmboot fails w/ control plane not ready for warmboot. This is because the test expects 2 responses for every ping packet sent to Loopback. This expectation is not correct after PR #9089 is merged.

Update the testcase to now only expect 1 icmp response for every icmp packet sent to Loopback0.
Updated the test to remove the earlier expectation of removing the packets that were sent by icmp_responder.

This essentially reverts part of older PR: #6968

How did you verify/test it?
Tested on a physical testbed and this test issue is not seen.
The test is now able to see the responses of ping packets

Co-authored-by: Vaibhav Hemant Dixit <[email protected]>

Author: zjswhhh

ansible/roles/test/files/ptftests/advanced-reboot.py

@@ -2032,11 +2032,6 @@ def pingDut(self):
 
         total_rcv_pkt_cnt = testutils.count_matched_packets_all_ports(self, self.ping_dut_exp_packet, self.vlan_ports, timeout=self.PKT_TOUT)
 
-        if self.is_dualtor:
-            # handle two-for-one icmp reply for dual tor (when vlan and dut mac are diff):
-            # icmp_responder will also generate a response for this ICMP req, ignore that reply
-            total_rcv_pkt_cnt = total_rcv_pkt_cnt - self.ping_dut_pkts
-
         self.log("Send %5d Received %5d ping DUT" % (self.ping_dut_pkts, total_rcv_pkt_cnt), True)
 
         return total_rcv_pkt_cnt