Update e2e tests and e2e test infrastructure (#414)

__tests__/e2e-test-csproj/test.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>$(TEST_TARGET_FRAMEWORK)</TargetFramework>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <!-- These packages will be downloaded over the network for testing proxy settings -->
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.5.0-preview-20170810-02" />
+    <PackageReference Include="MSTest.TestAdapter" Version="1.1.18" />
+    <PackageReference Include="MSTest.TestFramework" Version="1.1.18" />
+  </ItemGroup>
+
+</Project>