Fixes #30067

* EnC LocalSlotMappingTests for C# 8.0 patterns
* PDBTest
* EditAndContinueTest

Add nullable annotations to parts of the Workspace API

* Update dependencies from https://github.com/dotnet/arcade build 20190704.2

- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19354.2

* Update dependencies from https://github.com/dotnet/arcade build 20190705.2

- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19355.2

* Update dependencies from https://github.com/dotnet/arcade build 20190706.1

- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19356.1

* Update dependencies from https://github.com/dotnet/arcade build 20190708.1

- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19358.1

* Update dependencies from https://github.com/dotnet/arcade build 20190709.1

- Microsoft.DotNet.Arcade.Sdk - 1.0.0-beta.19359.1

Fixes #36963

The semantic model often creates ReducedExtensionMethods for the public API,
but the creation of ReducedExtensionMethod does constraint checking, which
requires a compilation, which isn't always available. This change removes constraint
checking from all creation of ReducedExtensionMethod and adds asserts that we
always have a compilation during constraint checking.

Fixes #37021

Don't show full attribute type name if in attribute name context

This also adds suppressions or asserts for places in Workspace.cs that
I enabled in my previous commit.

This adds a null check to Workspace.SetCurrentSolution;
the method would have thrown but not in a clean way.

Remove reflection based workaround for IRecursivePatternOperation

Completion should select IntelliCode item when possible

The API was made public in #36709, so we don't need a reflection based workaround

Fixes #36866

Merge release/dev16.3-preview1 to master

Add nullability information to GetSymbolInfo for invocations.

Add new refactoring feature to wrap chains of fluent calls.

Show suppression fixes in the light bulb under the squiggle/faded dia…

No blank line indentation

Prevents us from showing a light bulb under the squiggle/faded diagnostic without any code actions

Fixes #29589

Merge release/dev16.2 to release/dev16.3-preview1