* Add ServiceLayer.Test that overrides any other layer or workspace kind.

Mark all services used for testing with ServiceLayer.Test.
Remove WorkspaceKind.Test and set the kind of TestWorkspace to `host`.

* Move MockWorkspaceEventListenerProvider to Fatures test composition

* Enable solution crawler in diagnostic tests

Merge features/covariant-returns to master

Update IThreadingContext to support safe asynchronous shutdown

Fixes #30231

Merge master to features/covariant-returns

* Updated Error Message for CS1673

* TODOify

* Revert "Updated Error Message for CS1673"

This reverts commit 68fc0c80203b17f99ca025739c3edc07ba825795.

* PR Changes

* PR changes

* Update SolutionState.TrackedGeneratorDriver.cs

Rework compiler server abstraction

check if EditorAdaptersFactoryService gives us a null buffer

Also fix unintentional priority change for StartOnIdle.

Added search option for inline parameter name hints

fixes #43495

* Adjust overload resolution to handle explicit overrides that skip inheritance steps in binary compat scenarios
   Fixes #45798
* Skip a flaky test.
   Relates to #46361

Tweak delays we have before we start incrementally analyzing in OOP.

Consolidate the skip link for TestDefaultDiagnosticProviderRemove

Move open file diagnostic analysis to OOP

Merge release/dev16.8-preview1 to master

remove test that aserts .NET Standard should be prefered over .NET Framework

Do not persist winforms data to disk

Remove CPS restriction for applying rename during code fix

Fixes #45157

Check `Saved` on ProjectItem before calling Save