Production code changes to aid with test stabilization

Merge Roslyn.Test.Utilities.Traits with Microsoft.CodeAnalysis.Test.Utilities.Traits

Rev packages from beta2 to beta3

Re-enable integration tests against the newer image

We had disabled integration tests in -vs-deps since we were regularly
moving to new Visual Studio APIs and we were waiting to get new imaging
systems setup. Now that things have stabilized and we have new images,
we can use them.

Add names to code refactoring providers which don't have one

* Initial support for GotoDefinition in LINQ query syntax.

* Fixed naming issues.

* Fixed failing tests.

* Added support for Cast<> in from clause. Removed support for degenerated select clause. Reverted changes causing regressions.

* Added support for tokens to distinguish which MethodSymbol to return for a SyntaxNode that binds to more than one method. This adds support for range variable types and orderby.

* Fixed regression. Suppressed quick-info for degenerated query expressions.

* Added quick info tests according to the proposal.

* Added test for GotoDefinition. Moved logic for degenerated clauses to deeper layer.

* Added GotoDefinition for let test.

* Added test for incomplete orderby clause

* Code refactorings (Review feedback).

* PR feedback (nits)

* PR feedback (code comments).

* Revert changes in compiler.

* Revert changes in compiler (2).

* Added test for single from clause with out cast.

* Removed call to GetLanguageService and ValueTuple.Create

* Unify to return default;

* Corrected ISyntaxFactsService.IsQueryKeyword for VB and C#

Cancel pending work on workspace dispose

Move bootstrap phase to use NuPkg files

Add unit test leg on ES image