Add IConsole.Clear()

[kamran65536]

code in IConsole:

/// <summary>
/// Clears the console buffer and corresponding console window of display information.
/// </summary>
void Clear();

code in SystemConsole:

 /// <inheritdoc />
public void Clear()
{
     Console.Clear();
}

code in FakeConsole:

 /// <inheritdoc />
public void Clear()
{
}