Stabilize tst_QAbstractItemView::task200665_itemEntered()

It seems that sometimes QCursor::setPos() will not get the opportunity
to run the event loop before scrolling the list view unless we do it
explicitly.

Task-number: QTBUG-35060
Change-Id: Ic635bd8d1a4e3dbcadf9605e88197df6a0f69fc7
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>
Remove Mac unified toolbar workarounds.

QMainWindow::unifiedTitleAndToolBarOnMac() will
again return true, but the new implementation is
much more similar to the cross platform one so these
workarounds are not needed.

Task-number: QTBUG-34411
Change-Id: I8f63067f929c94aab252fc2e88f98fb94c870c44
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>
Implement QMainWindow::setUnifiedTitleAndToolBarOnMac

Fix a feature regression from Qt 4.

Unlike the Qt 4 implementation this does not move
the tool bars out of the QMainWindow while pretending
they are still there.

Instead, use setContentBorderThickness from the Cocoa
platform plugin to draw a background gradient that
unifies the title and toolbar area.

QToolBar can then draw itself with a transparent
background and let the gradient shine throughout.

This is a style-only change, toolbar behavior is
kept as-is.

[ChangeLog][Platform Specific Changes][OS X] Implemented
QMainWindow::setUnifiedTitleAndToolBarOnMac.

Task-number: QTBUG-34411
Change-Id: Idcaab6399f249b11edb1147856d9aece9923ab36
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>