Generate proper nullability annotation for IEquatable.Equals

* Update dependencies from https://github.com/dotnet/arcade build 20191106.10

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19556.10

* Update dependencies from https://github.com/dotnet/arcade build 20191107.20

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19557.20

When converting to LINQ calls, omit .Select(x => x) when possible.

Merge release/dev16.4 to master

Show QuickInfo on references to indexers

Completion for unimported extension methods

Show nullable annotations in the Change Signature dialog 

Respect RunAnalyzers and RunCodeAnalysisDuringLiveAnalysis project pr…

Fixes #38283

Completion: VSMac TypeScript completion doesn't commit with Enter

Reorder Suppression fixes to be above Configuration fixes in the lightbulb

Upgrade ICSharpCode.Decompiler to 5.0.2.5153

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19555.7

Merge release/dev16.4 to master

* Update dependencies from https://github.com/dotnet/arcade build 20191004.2

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19504.2

* Update dependencies from https://github.com/dotnet/arcade build 20191005.1

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19505.1

* Update dependencies from https://github.com/dotnet/arcade build 20191006.1

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19506.1

* Update dependencies from https://github.com/dotnet/arcade build 20191009.5

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19509.5

* Update dependencies from https://github.com/dotnet/arcade build 20191010.4

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19510.4

* Update dependencies from https://github.com/dotnet/arcade build 20191011.1

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19511.1

* Update dependencies from https://github.com/dotnet/arcade build 20191015.1

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19515.1

* Update dependencies from https://github.com/dotnet/arcade build 20191015.2

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19515.2

* Update dependencies from https://github.com/dotnet/arcade build 20191017.8

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19517.8

* Update dependencies from https://github.com/dotnet/arcade build 20191018.2

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19518.2

* Update dependencies from https://github.com/dotnet/arcade build 20191021.4

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19521.4

* Update dependencies from https://github.com/dotnet/arcade build 20191022.8

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19522.8

* Update dependencies from https://github.com/dotnet/arcade build 20191023.3

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19523.3

* Update dependencies from https://github.com/dotnet/arcade build 20191024.2

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19524.2

* Update dependencies from https://github.com/dotnet/arcade build 20191025.2

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19525.2

* Update dependencies from https://github.com/dotnet/arcade build 20191026.1

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19526.1

* Update dependencies from https://github.com/dotnet/arcade build 20191027.3

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19527.3

* Update dependencies from https://github.com/dotnet/arcade build 20191028.5

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19528.5

* Update dependencies from https://github.com/dotnet/arcade build 20191029.9

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19529.9

* Update dependencies from https://github.com/dotnet/arcade build 20191030.15

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19530.15

* Update dependencies from https://github.com/dotnet/arcade build 20191031.14

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19531.14

* Update dependencies from https://github.com/dotnet/arcade build 20191101.3

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19551.3

* Update dependencies from https://github.com/dotnet/arcade build 20191102.1

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19552.1

* Update dependencies from https://github.com/dotnet/arcade build 20191104.3

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19554.3

* Work around dotnet/wpf#1718 by not embedding untracked source

* Pack Content for analyzer packages

Fixes #39564

Fixes #31784

In cases where converting to LINQ calls would leave no LINQ calls at all,
we leave the .Select(x => x) in case the user is trying to do some different
operation.

Merge release/dev16.4 to master

Switch some calls to ThreadHelper.ThrowIfNotOnUIThread to something else

Cleaning up the documentation on our compiler toolset packages to make
the supported use cases explicitly clear. Previously this information
was only avaliable in scattered issues throughout the repsitory
([example](https://github.com/dotnet/roslyn/issues/38312)).

The package description is likely the best place for this information.

Update release/dev16.4 version to -beta4

- Control flow graph builder
- Using decl Ioperation tests
- PublicAPI.Unshipped.txt