Normalize all file headers to the expected Apache 2.0 license

\n\nCommit migrated from dotnet/extensions@cec6e75

Author: sharwell

src/Caching/SqlServer/test/TestOptions.cs

@@ -1,3 +1,6 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
 using Microsoft.Extensions.Options;
 
 namespace Microsoft.Extensions.Caching.SqlServer

src/Caching/samples/ProfilingSample/Program.cs

@@ -1,3 +1,6 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;