[release/3.0] Update dependencies from aspnet/Extensions (dotnet/aspnetcore-tooling#975)

* Update dependencies from https://github.com/aspnet/Extensions build 20190815.2

- Microsoft.AspNetCore.BenchmarkRunner.Sources - 3.0.0-preview9.19415.2
- Microsoft.AspNetCore.Testing - 3.0.0-preview9.19415.2
- Microsoft.Extensions.CommandLineUtils.Sources - 3.0.0-preview9.19415.2
- Microsoft.Extensions.HashCodeCombiner.Sources - 3.0.0-preview9.19415.2
- Microsoft.Extensions.NonCapturingTimer.Sources - 3.0.0-preview9.19415.2
- Microsoft.Extensions.Logging - 3.0.0-preview9.19415.2

Dependency coherency updates

- Microsoft.NETCore.App.Runtime.win-x64 - 3.0.0-preview9-19414-17 (parent: Microsoft.Extensions.Logging)
- Microsoft.Extensions.DependencyModel - 3.0.0-preview9-19414-17 (parent: Microsoft.Extensions.Logging)
- Microsoft.NETCore.App.Ref - 3.0.0-preview9-19414-17 (parent: Microsoft.Extensions.Logging)
- Microsoft.Net.Compilers.Toolset - 3.3.0-beta3-19415-01 (parent: Microsoft.Extensions.Logging)

* Update dependencies from https://github.com/aspnet/Extensions build 20190814.4

- Microsoft.AspNetCore.BenchmarkRunner.Sources - 3.0.0-preview9.19414.4
- Microsoft.AspNetCore.Testing - 3.0.0-preview9.19414.4
- Microsoft.Extensions.CommandLineUtils.Sources - 3.0.0-preview9.19414.4
- Microsoft.Extensions.HashCodeCombiner.Sources - 3.0.0-preview9.19414.4
- Microsoft.Extensions.NonCapturingTimer.Sources - 3.0.0-preview9.19414.4
- Microsoft.Extensions.Logging - 3.0.0-preview9.19414.4

* Update dependencies from https://github.com/aspnet/Extensions build 20190815.2

- Microsoft.AspNetCore.BenchmarkRunner.Sources - 3.0.0-preview9.19415.2
- Microsoft.AspNetCore.Testing - 3.0.0-preview9.19415.2
- Microsoft.Extensions.CommandLineUtils.Sources - 3.0.0-preview9.19415.2
- Microsoft.Extensions.HashCodeCombiner.Sources - 3.0.0-preview9.19415.2
- Microsoft.Extensions.NonCapturingTimer.Sources - 3.0.0-preview9.19415.2
- Microsoft.Extensions.Logging - 3.0.0-preview9.19415.2

* React to namespace removal
\n\nCommit migrated from 543a1ae2a3

src/Razor/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorProjectFileSystemTest.cs

@@ -5,7 +5,6 @@ using System;
 using System.IO;
 using System.Linq;
 using Microsoft.AspNetCore.Testing;
-using Microsoft.AspNetCore.Testing.xunit;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Language

src/Razor/Microsoft.AspNetCore.Razor.Tools/test/ServerLifecycleTest.cs

@@ -7,7 +7,7 @@ using System.Diagnostics;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Testing.xunit;
+using Microsoft.AspNetCore.Testing;
 using Moq;
 using Xunit;
 

src/Razor/Microsoft.NET.Sdk.Razor/test/IntegrationTests/ApplicationPartDiscoveryIntegrationTest.cs

@@ -3,7 +3,7 @@
 
 using System.IO;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Testing.xunit;
+using Microsoft.AspNetCore.Testing;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests

src/Razor/Microsoft.NET.Sdk.Razor/test/IntegrationTests/BuildIncrementalismTest.cs

@@ -7,7 +7,7 @@ using System.IO;
 using System.Linq;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Testing.xunit;
+using Microsoft.AspNetCore.Testing;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests

src/Razor/Microsoft.NET.Sdk.Razor/test/IntegrationTests/BuildIntegrationTest.cs

@@ -7,7 +7,7 @@ using System.Linq;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
-using Microsoft.AspNetCore.Testing.xunit;
+using Microsoft.AspNetCore.Testing;
 using Microsoft.Extensions.DependencyModel;
 using Xunit;
 

src/Razor/Microsoft.NET.Sdk.Razor/test/IntegrationTests/BuildIntegrationTest11.cs

@@ -2,7 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Testing.xunit;
+using Microsoft.AspNetCore.Testing;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests

src/Razor/Microsoft.NET.Sdk.Razor/test/IntegrationTests/BuildIntegrationTest22NetFx.cs

@@ -4,7 +4,7 @@
 using System;
 using System.IO;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Testing.xunit;
+using Microsoft.AspNetCore.Testing;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests

src/Razor/Microsoft.NET.Sdk.Razor/test/IntegrationTests/BuildServerIntegrationTest.cs

@@ -7,7 +7,6 @@ using System.IO;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Testing;
-using Microsoft.AspNetCore.Testing.xunit;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests

src/Razor/Microsoft.NET.Sdk.Razor/test/IntegrationTests/BuildWithComponentsIntegrationTest.cs

@@ -3,7 +3,7 @@
 
 using System.IO;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Testing.xunit;
+using Microsoft.AspNetCore.Testing;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests