D28224: Improve tests behaviour on set ups with high dpi

Zren added inline comments.

INLINE COMMENTS

> screenedge.cpp:730
>  {
> -    QWidget w;
> -    m_cornerOffset = (w.physicalDpiX() + w.physicalDpiY() + 5) / 6;
> +    m_cornerOffset = (Screens::self()->physicalDpiX(0) + Screens::self()->physicalDpiX(0) + 5) / 6;
>  

Was `(X + X + 5) / 6` deliberate here? The old behavior was `(X + Y + 5) / 6`.

REPOSITORY
  R108 KWin

REVISION DETAIL
  https://phabricator.kde.org/D28224

To: apol, #kwin, davidedmundson
Cc: Zren, kwin, Orage, cacarry, LeGast00n, The-Feren-OS-Dev, cblack, jraleigh, zachus, fbampaloukas, mkulinski, ragreen, jackyalcine, iodelay, crozbo, bwowk, ZrenBot, ngraham, alexeymin, himcesjf, lesliezhai, ali-mohamed, hardening, romangg, jensreuterberg, abetts, sebas, apol, ahiemstra, mart