Updated NUnit packages, removed NUnitLite added packages for dotnet and Visual…

Updated NUnit packages, removed NUnitLite added packages for dotnet and Visual Studio, changed dotnet command in buildall to dotnet test, and deleted Program.cs (because it's no longer required).

csharp/buildall.sh

@@ -14,4 +14,4 @@ echo Running tests.
 # If we want to test the .NET 4.5 version separately, we could
 # run Mono explicitly. However, we don't have any differences between
 # the .NET 4.5 and netstandard1.0 assemblies.
-dotnet run -c $CONFIG -f netcoreapp1.0 -p $SRC/Google.Protobuf.Test/Google.Protobuf.Test.csproj
+dotnet test -c $CONFIG -f netcoreapp1.0 $SRC/Google.Protobuf.Test/Google.Protobuf.Test.csproj

csharp/src/Google.Protobuf.Test/Google.Protobuf.Test.csproj

 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <OutputType>Exe</OutputType>
     <TargetFrameworks>net451;netcoreapp1.0</TargetFrameworks>
     <AssemblyOriginatorKeyFile>../../keys/Google.Protobuf.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
@@ -14,8 +13,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="NUnit" Version="3.6.1" />
-    <PackageReference Include="NUnitLite" Version="3.6.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.5.0" />
+    <PackageReference Include="NUnit" Version="3.9.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="3.9.0" />
   </ItemGroup>
 
   <!-- 
@@ -26,5 +26,5 @@
   <PropertyGroup Condition="'$(OS)' != 'Windows_NT'">
     <TargetFrameworks>netcoreapp1.0</TargetFrameworks>
   </PropertyGroup>
-  
+
 </Project>

csharp/src/Google.Protobuf.Test/Program.cs

-#region Copyright notice and license
-// Protocol Buffers - Google's data interchange format
-// Copyright 2017 Google Inc.  All rights reserved.
-// https://developers.google.com/protocol-buffers/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-#endregion
-using NUnitLite;
-using System.Reflection;
-
-namespace Google.Protobuf.Test
-{
-    class Program
-    {
-        public static int Main(string[] args)
-        {
-            #if NET35
-                return new AutoRun(typeof(Program).Assembly).Execute(args);
-            #else
-                return new AutoRun(typeof(Program).GetTypeInfo().Assembly).Execute(args);
-            #endif
-        }
-    }
-}
\ No newline at end of file