QAbstractFileIconEngine stores the generated pixmap in a QPixmapCache
with the size as key. This is wrong as the size is multiplied by the
current devicePixelRatio so this has to be done also for the key.
Change-Id: I6d8ceedc950d23abf9c4d79d92e86848b9508c9b
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 83ff179f85559af880d28d7832d44f95c5ce9616)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit da4e9b7637f3ac71397c91109c460ca781abbc7a)