[ChangeLog][QtCore][QFuture] Introduce
QtFuture::makeReadyRangeFuture(). This method takes a container
which has input iterators and returns a multi-value
QFuture<ValueType>, where ValueType is the underlying type of
the input container.
This commit also replaces the usage of buggy
QtFuture::makeReadyFuture(const QList<T> &) overload with the new
method.
Task-number: QTBUG-109677
Change-Id: I019e62eac74c643d88a65b3cc0085bc7c33bc712
Reviewed-by: Marc Mutz <marc.mutz@qt.io>