Update Qos sai tests for no lossless queue feature

1. Update qos sai lossy tests because all lossless queues has changed as lossy queues
2. Skip fixture reaseAllports for mellanox device, because after qos test is finished, the teardown will do config reload, it will restore the config of ports, we don't need this fixture before running tests. Also it can save 2 minutes
3. Relevant PRs: sonic-net/sonic-buildimage#21427, sonic-net/sonic-buildimage#21056

Author: JibinBao

tests/qos/files/mellanox/qos_param_generator.py

@@ -236,6 +236,11 @@ def calculate_parameters(self):
         self.qos_params_mlnx['wm_pg_shared_lossy'].update(wm_shared_lossy)
         wm_shared_lossy["pkts_num_margin"] = 8
         self.qos_params_mlnx['wm_q_shared_lossy'].update(wm_shared_lossy)
+        if 'lossy_dscp' in self.egressLossyProfile:
+            lossy_queue['dscp'] = self.egressLossyProfile['lossy_dscp']
+            self.qos_params_mlnx['wm_pg_shared_lossy']['dscp'] = self.egressLossyProfile['lossy_dscp']
+            self.qos_params_mlnx['wm_q_shared_lossy']['dscp'] = self.egressLossyProfile['lossy_dscp']
+            self.qos_params_mlnx['wm_q_shared_lossy']['queue'] = self.egressLossyProfile['lossy_queue']
 
         wm_buf_pool_lossless = self.qos_params_mlnx['wm_buf_pool_lossless']
         wm_buf_pool_lossless['pkts_num_trig_pfc'] = pkts_num_trig_pfc

tests/qos/qos_sai_base.py

@@ -1747,10 +1747,13 @@ def releaseAllPorts(
             Raises:
                 RunAnsibleModuleFail if ptf test fails
         """
-        self.runPtfTest(
-            ptfhost, testCase="sai_qos_tests.ReleaseAllPorts",
-            testParams=dutTestParams["basicParams"]
-        )
+        if isMellanoxDevice(duthosts[0]):
+            logger.info("skip reaseAllports fixture for mellanox device")
+        else:
+            self.runPtfTest(
+                ptfhost, testCase="sai_qos_tests.ReleaseAllPorts",
+                testParams=dutTestParams["basicParams"]
+            )
 
     def __loadSwssConfig(self, duthost):
         """
@@ -2069,12 +2072,26 @@ def egressLossyProfile(
 
         srcport = dutConfig["dutInterfaces"][dutConfig["testPorts"]["src_port_id"]]
 
+        is_lossy_queue_only = False
+
         if srcport in dualtor_ports_for_duts:
             queues = "0-1"
         else:
-            queues = "0-2"
+            if isMellanoxDevice(duthost):
+                profile_content = dut_asic.run_redis_cmd(
+                    argv=["redis-cli", "-n", 0, "keys", f'BUFFER_PG_TABLE:{srcport}:*-4'])
+                if not profile_content:
+                    is_lossy_queue_only = True
+                    logger.info(f"{srcport} has only lossy queue")
+            if is_lossy_queue_only:
+                is_lossy_queue_only = True
+                queue_table_postfix_list = ['1-2', '3', '4']
+                queue_to_dscp_map = {'1-2': '1', '3': '3', '4': '5'}
+                queues = random.choice(queue_table_postfix_list)
+            else:
+                queues = "0-2"
 
-        yield self.__getBufferProfile(
+        egress_lossy_profile = self.__getBufferProfile(
             request,
             dut_asic,
             duthost.os_version,
@@ -2083,6 +2100,12 @@ def egressLossyProfile(
             srcport,
             queues
         )
+        if is_lossy_queue_only:
+            egress_lossy_profile['lossy_dscp'] = queue_to_dscp_map[queues]
+            egress_lossy_profile['lossy_queue'] = '1' if queues == '1-2' else queues
+        logger.info(f"egressLossyProfile: {egress_lossy_profile}")
+
+        yield egress_lossy_profile
 
     @pytest.fixture(scope='class')
     def losslessSchedProfile(