Merge pull request #573 from dotnet/indexing

Fix indexing issue when processing nested actions.

src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/CodeActionTest`1.cs

@@ -107,7 +107,7 @@ protected virtual ImmutableArray<CodeAction> FilterCodeActions(ImmutableArray<Co
                     if (!nestedActions.IsEmpty)
                     {
                         builder.RemoveAt(i);
-                        for (var j = nestedActions.Length - 1; i >= 0; i--)
+                        for (var j = nestedActions.Length - 1; j >= 0; j--)
                         {
                             builder.Insert(i, nestedActions[j]);
                         }