Fix license header on newly-added files

src/libraries/System.Private.CoreLib/src/System/Runtime/Serialization/SerializationInfo.SerializationGuard.cs

@@ -1,6 +1,5 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // 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.Security;
 using System.Threading;

src/libraries/System.Private.CoreLib/src/System/SecureAppContext.cs

@@ -1,6 +1,5 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
 
 namespace System
 {

src/libraries/System.Runtime.Serialization.Formatters/tests/DisableBitTests.cs

@@ -1,6 +1,5 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // 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.IO;
 using System.Runtime.Serialization.Formatters.Binary;

src/libraries/System.Runtime/tests/System/AppContext/SecureAppContext.cs

@@ -1,6 +1,5 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // 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.Reflection;
 using Microsoft.DotNet.RemoteExecutor;