Added dependencies projects to other solutions

Invoke next handler in case if no signature help providers can be fou…

Unified dependencies to xUnit

Update Solution.GetProject(IAssemblySymbol) [Fixes unit test flakiness]

Remove redundant instance of SpeculativeTCompletionProvider inside CSharpCompletionService

invoke next handler in case if no signature help providers can be found (i.e. if document for the text snapshot cannot be found)

Allow interactive window evaluation of empty line.

Reference as much of the VS SDK as we can via NuGet packages

Merge stabilization into master

Fixes #10132

Adds a map from ISymbol (assembly or module symbols) to ProjectId so we can find projects for skeleton assemblies even after its compilation could have been GC'd.

You should be able to navigate to items that are in generated code.

Fixes #8009

I broke this in e0dfce11.

This brought along some references to Microsoft.VisualStudio.Threading
that we previously didn't have. Nothing was wrong with this, but it
meant I had to fix some namespace qualifications that were assuming the
"Threading" namespace was unambiguous.

Move groovy to dotnet-ci standard functions

Use the standard archive function for the dotnet-ci tools.

This was only previously necessary on Mac / Linux because of our Mono installation process.  This is no longer done now that we are on CoreClr.

VB: Always import instance fields for an Enum type in order to be able to infer underlying type of its elements.

Unify NuGet dependencies across the tree

Delete the last remaining project.lock.json

These keep coming back.

To prevent projects across the tree from having different dependencies, we unify
external package dependencies by creating empty C# projects that represent them.
We then make use of project.json package inheritance (where a project inherits
all packages dependencies from their dependencies) to unify it across the tree.

No projects outside of this tree, should be directly referencing versions of
these dependencies manually.

For this check-in I've tackled Metadata, Reflection, and DiaSymReader. Will tackle
the rest in future commits.

some code clean up and made active and project state to be merged when a file is closed

Go to the start of the current member first.

Add netstandard TFM to workspaces nuspecs

Merge stabilization into master

Merge master to stabilization