Remove redundant using statement

Author: edwardneal

src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/SqlClient/LocalAppContextSwitchesTest.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
 using Xunit;
 
 namespace Microsoft.Data.SqlClient.UnitTests;

src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/SqlClient/SqlCommandSetTest.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Data;
 using System.Reflection;
 using Xunit;