Upgrade Roslyn for tests to 3.3.1.

ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -42,8 +42,8 @@
   <ItemGroup>
     <PackageReference Include="DiffLib" Version="2017.7.26.1241" />
     <PackageReference Include="Microsoft.Build.Locator" Version="1.2.2" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.3.0-beta1-final" />
-    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.3.0-beta1-final" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.3.1" />
+    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.3.1" />
     <PackageReference Include="Microsoft.DiaSymReader.Converter.Xml" Version="1.1.0-beta1-63314-01" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.13.0" />
     <PackageReference Include="System.Collections.Immutable" Version="1.5.0" />

ILSpy.Tests/ILSpy.Tests.csproj

@@ -42,8 +42,8 @@
 
   <ItemGroup>
     <PackageReference Include="DiffLib" Version="2017.7.26.1241" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.0.0-beta4-final" />
-    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.0.0-beta4-final" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.3.1" />
+    <PackageReference Include="Microsoft.CodeAnalysis.VisualBasic" Version="3.3.1" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.13.0" />
     <PackageReference Include="System.Collections.Immutable" Version="1.5.0" />
     <PackageReference Include="NUnit" Version="3.11.0" />