Add unit tests to System.ComponentModel.Design.* components

Add unit tests (if not exists) for

Methods:
System.ComponentModel.Design.UndoEngine
- [ ] M:System.ComponentModel.Design.UndoEngine.#ctor(System.IServiceProvider)
- [ ] M:System.ComponentModel.Design.UndoEngine.DiscardUndoUnit(System.ComponentModel.Design.UndoEngine.UndoUnit)
- [ ] M:System.ComponentModel.Design.UndoEngine.Dispose(System.Boolean)
- [ ] M:System.ComponentModel.Design.UndoEngine.get_Enabled
- [ ] M:System.ComponentModel.Design.UndoEngine.get_UndoInProgress
- [ ] M:System.ComponentModel.Design.UndoEngine.GetService(System.Type)
- [ ] M:System.ComponentModel.Design.UndoEngine.set_Enabled(System.Boolean)

System.ComponentModel.Design.DesignSurface
- [ ] M:System.ComponentModel.Design.DesignSurface.add_Flushed(System.EventHandler)
- [ ] M:System.ComponentModel.Design.DesignSurface.remove_Flushed(System.EventHandler)

System.ComponentModel.Design.InheritanceService
- [ ] M:System.ComponentModel.Design.InheritanceService.#ctor
- [ ] M:System.ComponentModel.Design.InheritanceService.IgnoreInheritedMember(System.Reflection.MemberInfo,System.ComponentModel.IComponent)

System.ComponentModel.Design.DesignerActionMethodItem
- [ ] M:System.ComponentModel.Design.DesignerActionMethodItem.#ctor(System.ComponentModel.Design.DesignerActionList,System.String,System.String,System.String,System.String,System.Boolean)
- [ ] M:System.ComponentModel.Design.DesignerActionMethodItem.#ctor(System.ComponentModel.Design.DesignerActionList,System.String,System.String,System.String,System.String,System.Boolean)
- [ ] M:System.ComponentModel.Design.DesignerActionMethodItem.get_IncludeAsDesignerVerb
- [ ] M:System.ComponentModel.Design.DesignerActionMethodItem.Invoke

System.ComponentModel.Design.DesignerActionPropertyItem
- [ ] M:System.ComponentModel.Design.DesignerActionPropertyItem.#ctor(System.String,System.String,System.String)
- [ ] M:System.ComponentModel.Design.DesignerActionPropertyItem.get_MemberName

2) Classes:

- [ ] System/ComponentModel/Design/DesignSurfaceServiceContainer.cs
- [ ] System/ComponentModel/Design/DesignerActionItem.cs
- [ ] System/ComponentModel/Design/DesignerActionList.cs
- [ ] System/ComponentModel/Design/DesignerHost.cs
- [ ] System/ComponentModel/Design/ExceptionCollection.cs
- [ ] System/ComponentModel/Design/ExtenderProviderService.cs
- [ ] System/ComponentModel/Design/HostDesigntimeLicenseContext.cs
- [ ] System/ComponentModel/Design/LoadedEventHandler.cs
- [ ] System/ComponentModel/Design/ReferenceService.cs
- [ ] System/ComponentModel/Design/StatusCommandUI.cs

Epic: #716
Related issues: #221, #469, #592
Related PRs: #606