Added leak test for named controls.
Added leak test for named controls.

As previously they were leaking before recent name scope fixes.

MrDaedra/Avalonia,SuperJMN/Avalonia,SuperJMN/Avalonia,grokys/Perspex,wieslawsoltes/Perspex,wieslawsoltes/Perspex,susloparovdenis/Perspex,wieslawsoltes/Perspex,jazzay/Perspex,jkoritzinsky/Avalonia,Perspex/Perspex,MrDaedra/Avalonia,AvaloniaUI/Avalonia,jkoritzinsky/Avalonia,grokys/Perspex,AvaloniaUI/Avalonia,SuperJMN/Avalonia,AvaloniaUI/Avalonia,susloparovdenis/Perspex,wieslawsoltes/Perspex,punker76/Perspex,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,jkoritzinsky/Perspex,OronDF343/Avalonia,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,wieslawsoltes/Perspex,AvaloniaUI/Avalonia,SuperJMN/Avalonia,wieslawsoltes/Perspex,susloparovdenis/Avalonia,wieslawsoltes/Perspex,SuperJMN/Avalonia,SuperJMN/Avalonia,susloparovdenis/Avalonia,OronDF343/Avalonia,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,SuperJMN/Avalonia,AvaloniaUI/Avalonia,akrisiun/Perspex,jkoritzinsky/Avalonia,Perspex/Perspex