update skip condition for cisco T2 (sonic-net#11553)

1, testQosSaiLosslessVoq requires split-voq or fair-voq, skip vanguard(cisco Q200 longlink) since it uses default-voq.
2. testQosSaiSharedReservationSize, skip gibraltar(cisco Q200 linecard) since not enough ports.
Skip shared_res_size_2 for pacific(cisco Q100 linecard) since on pacific, SQG thresholds have no impact on XOFF thresholds.

tests/qos/qos_sai_base.py

@@ -2243,3 +2243,13 @@ def populate_arp_entries(
             self.runPtfTest(
                 ptfhost, testCase=saiQosTest, testParams=testParams
             )
+
+    @pytest.fixture(scope="function", autouse=False)
+    def skip_longlink(self, dutQosConfig):
+        portSpeedCableLength = dutQosConfig["portSpeedCableLength"]
+        match = re.search("_([0-9]*)m", portSpeedCableLength)
+        if match and int(match.group(1)) > 2000:
+            pytest.skip(
+                "This test is skipped for longlink.")
+        yield
+        return

tests/qos/test_qos_sai.py

@@ -684,7 +684,7 @@ def testQosSaiPfcXonLimit(
          "lossless_voq_3", "lossless_voq_4"])
     def testQosSaiLosslessVoq(
             self, LosslessVoqProfile, ptfhost, dutTestParams, dutConfig,
-            dutQosConfig, get_src_dst_asic_and_duts
+            dutQosConfig, get_src_dst_asic_and_duts, skip_longlink
     ):
         """
             Test QoS SAI XOFF limits for various voq mode configurations
@@ -883,6 +883,14 @@ def testQosSaiSharedReservationSize(
             Raises:
                 RunAnsibleModuleFail if ptf test fails
         """
+        if ('modular_chassis' in get_src_dst_asic_and_duts['src_dut'].facts and
+                get_src_dst_asic_and_duts['src_dut'].facts["modular_chassis"] == "True"):
+            if dutConfig['dstDutAsic'] != "pac":
+                pytest.skip("This test is skipped since not enough ports on cisco-8000 "
+                            "T2 Q200.")
+            if "shared_res_size_2" in sharedResSizeKey:
+                pytest.skip("This test is skipped since on cisco-8000 Q100, "
+                            "SQG thresholds have no impact on XOFF thresholds.")
 
         qosConfig = dutQosConfig["param"]
         src_dut_index = get_src_dst_asic_and_duts['src_dut_index']