Fix clipping of QTextList decorators.

List decorators may be clipped if you set a large font size and/or
small indent for a QTextList. This fix is to prevent clipping by
moving list decorators and items to left (or to right in case of
right to left layouts) so that the list decorator is always painted
inside the layout.

This commit fixes painting related issue, so auto test is not needed.
The manual test program can be used for verification purposes.

Task-number: QTBUG-5111
Change-Id: I0de01f4d6b833289948ac29e38dd3cc8ab9bca9e
(cherry picked from commit qtbase/ad443dfb1d8e9096c4913686aa2ed0bc9b3f5de7)
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>