add vb.net tests

FreeSql.Tests.VB/g.vb

@@ -0,0 +1,18 @@
+Imports System.Threading
+
+Public Class g
+
+    Shared sqlserverLazy As Lazy(Of IFreeSql) = New Lazy(Of IFreeSql)(New Func(Of IFreeSql)(Function() New FreeSqlBuilder() _
+        .UseConnectionString(DataType.SqlServer, "Data Source=.;Integrated Security=True;Initial Catalog=freesqlTest;Pooling=true;Max Pool Size=3") _
+        .UseAutoSyncStructure(True) _
+        .UseMonitorCommand(Sub(cmd) Trace.WriteLine("\r\n线程" & Thread.CurrentThread.ManagedThreadId & ": " & cmd.CommandText)) _
+        .UseLazyLoading(True) _
+        .Build()))
+
+    Public Shared ReadOnly Property sqlserver As IFreeSql
+        Get
+            Return sqlserverLazy.Value
+        End Get
+    End Property
+
+End Class