[trim]: Add Packet Trimming Port/Queue stats to VS lib (#1608)

Signed-off-by: Nazarii Hnydyn <[email protected]>

**DEPENDS:**
1. #1575

**HLD:** sonic-net/SONiC#1898

#### A picture of a cute animal (not mandatory but encouraged)
```
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 / \ __ / ------
 / / \( )/ -----
 ////// ' \/ ` ---
 //// / // : : ---
 // / / /` '--
// //..\\
 ====UU====UU====
 '//||\\`
 ''``
```

Author: mssonicbld

unittest/vslib/TestSwitchMLNX2700.cpp

@@ -600,30 +600,37 @@ TEST(SwitchMLNX2700, test_stats_query_capability)
             std::make_shared<RealObjectIdManager>(0, scc),
             sc);
 
-    sai_stat_capability_t capability_list[91];
+    std::vector<sai_stat_capability_t> capability_list;
     sai_stat_capability_list_t stats_capability;
-    stats_capability.count = 1;
-    stats_capability.list = capability_list;
+
     /* Get queue stats capability */
+    stats_capability.count = 0;
+    stats_capability.list = nullptr;
+
     EXPECT_EQ(sw.queryStatsCapability(0x2100000000,
                                           SAI_OBJECT_TYPE_QUEUE,
                                           &stats_capability),
                                           SAI_STATUS_BUFFER_OVERFLOW);
 
-    stats_capability.count = SAI_QUEUE_STAT_DELAY_WATERMARK_NS;
+    capability_list.resize(stats_capability.count);
+    stats_capability.list = capability_list.data();
 
     EXPECT_EQ(sw.queryStatsCapability(0x2100000000,
                                           SAI_OBJECT_TYPE_QUEUE,
                                           &stats_capability),
                                           SAI_STATUS_SUCCESS);
 
     /* Get port stats capability */
-    stats_capability.count = 1;
+    stats_capability.count = 0;
+    stats_capability.list = nullptr;
+
     EXPECT_EQ(sw.queryStatsCapability(0x2100000000,
                                           SAI_OBJECT_TYPE_PORT,
                                           &stats_capability),
                                           SAI_STATUS_BUFFER_OVERFLOW);
-    stats_capability.count = 91;
+
+    capability_list.resize(stats_capability.count);
+    stats_capability.list = capability_list.data();
 
     EXPECT_EQ(sw.queryStatsCapability(0x2100000000,
                                           SAI_OBJECT_TYPE_PORT,

unittest/vslib/TestVirtualSwitchSaiInterface.cpp

@@ -161,35 +161,41 @@ TEST_F(VirtualSwitchSaiInterfaceTest, bulkGet)
 
 TEST_F(VirtualSwitchSaiInterfaceTest, queryStatsCapability)
 {
-    sai_stat_capability_t capability_list[91];
+    std::vector<sai_stat_capability_t> capability_list;
     sai_stat_capability_list_t stats_capability;
-    stats_capability.list = capability_list;
 
     /* Queue stats capability get */
-    stats_capability.count = 1;
+    stats_capability.count = 0;
+    stats_capability.list = nullptr;
 
     EXPECT_EQ(SAI_STATUS_BUFFER_OVERFLOW,
             m_vssai->queryStatsCapability(
                 m_swid,
                 SAI_OBJECT_TYPE_QUEUE,
                 &stats_capability));
 
+    capability_list.resize(stats_capability.count);
+    stats_capability.list = capability_list.data();
+
     EXPECT_EQ(SAI_STATUS_SUCCESS,
             m_vssai->queryStatsCapability(
                 m_swid,
                 SAI_OBJECT_TYPE_QUEUE,
                 &stats_capability));
 
     /* Port stats capability get */
-    stats_capability.count = 1;
+    stats_capability.count = 0;
+    stats_capability.list = nullptr;
 
     EXPECT_EQ(SAI_STATUS_BUFFER_OVERFLOW,
             m_vssai->queryStatsCapability(
                 m_swid,
                 SAI_OBJECT_TYPE_PORT,
                 &stats_capability));
 
-    stats_capability.count = 91;
+    capability_list.resize(stats_capability.count);
+    stats_capability.list = capability_list.data();
+
     EXPECT_EQ(SAI_STATUS_SUCCESS,
             m_vssai->queryStatsCapability(
                 m_swid,
@@ -199,35 +205,41 @@ TEST_F(VirtualSwitchSaiInterfaceTest, queryStatsCapability)
 
 TEST_F(VirtualSwitchSaiInterfaceTest, queryStatsStCapability)
 {
-    sai_stat_st_capability_t capability_list[91];
+    std::vector<sai_stat_st_capability_t> capability_list;
     sai_stat_st_capability_list_t stats_capability;
-    stats_capability.list = capability_list;
 
     /* Queue stats capability get */
-    stats_capability.count = 1;
+    stats_capability.count = 0;
+    stats_capability.list = nullptr;
 
     EXPECT_EQ(SAI_STATUS_BUFFER_OVERFLOW,
               m_vssai->queryStatsStCapability(
                   m_swid,
                   SAI_OBJECT_TYPE_QUEUE,
                   &stats_capability));
 
+    capability_list.resize(stats_capability.count);
+    stats_capability.list = capability_list.data();
+
     EXPECT_EQ(SAI_STATUS_SUCCESS,
               m_vssai->queryStatsStCapability(
                   m_swid,
                   SAI_OBJECT_TYPE_QUEUE,
                   &stats_capability));
 
     /* Port stats capability get */
-    stats_capability.count = 1;
+    stats_capability.count = 0;
+    stats_capability.list = nullptr;
 
     EXPECT_EQ(SAI_STATUS_BUFFER_OVERFLOW,
               m_vssai->queryStatsStCapability(
                   m_swid,
                   SAI_OBJECT_TYPE_PORT,
                   &stats_capability));
 
-    stats_capability.count = 91;
+    capability_list.resize(stats_capability.count);
+    stats_capability.list = capability_list.data();
+
     EXPECT_EQ(SAI_STATUS_SUCCESS,
               m_vssai->queryStatsStCapability(
                   m_swid,