Added missing copyrights to test files

src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IDynamicMemberReferenceExpression.cs

-using Microsoft.CodeAnalysis.CSharp.Syntax;
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Test.Utilities;
 using Xunit;
 

src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IDynamicMemberReferenceExpression.vb

-Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
 
 Namespace Microsoft.CodeAnalysis.VisualBasic.UnitTests.Semantics