Expose ProjectWorkspaceState on ProjectSnapshot.

- There are too many components that need this property directly to compare two different project snapshots. Should have exposed this to begin with.
- Also found that `ProjectWorkspaceState` was incorrectly marked public, changed it to internal.

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/DefaultProjectSnapshot.cs

@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
 
 namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
@@ -42,6 +41,8 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
 
         public override IReadOnlyList<TagHelperDescriptor> TagHelpers => State.TagHelpers;
 
+        public override ProjectWorkspaceState ProjectWorkspaceState => State.ProjectWorkspaceState;
+
         public override DocumentSnapshot GetDocument(string filePath)
         {
             lock (_lock)

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshot.cs

@@ -18,6 +18,8 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem
 
         public virtual IReadOnlyList<TagHelperDescriptor> TagHelpers { get; }
 
+        public virtual ProjectWorkspaceState ProjectWorkspaceState { get; }
+
         public abstract RazorProjectEngine GetProjectEngine();
 
         public abstract DocumentSnapshot GetDocument(string filePath);