Testing - Check Dispose call timing for OutOfProcess tests

[govert]

From @eeaston:

Running the dispose method when using OutOfProcess mode throws errors due to I think closed process handles.

    // Clean-up for the class is in the IDisposable.Dispose implementation
    public void Dispose()
    {
        wb.Close(SaveChanges: false);
    }

[Sergey-Vlasov]

Can he send us a complete example? As we don't have special support for clean-up and it is completely custom code.

And if a workbook is opened in ExcelFact declaration,

                    Util.Workbook.Close(false);
                    Util.Workbook = null;

performed automatically on test completion.