[WinRT] Dispatcher memory corruption

bool QEventDispatcherWinRT::event(QEvent *e) has a really bad memory corruption caused by copying into a dangling reference.

A reference varaible info taken from d->timerInfos:

WinRTTimerInfo &info = d->timerInfos[id];

The same reference later copy assigned even though it may be danging after d->timerInfos modifications.

info = d->timerInfos[id];

It has the right idea of getting a new "reference", but that's not how references work and this is just a balant copy assignment into potentally dangling reference.

And to top it most of the time the heap corruption causes random crashes elsewhere. There is more reckless reference usage that could use a review, but this is the biggest random heap corruptor that I have finally cought in the WinRT plugin.

Two simple fixes attached, I personally prefer the scoped with minor reordering apporach to prevent accidental usage of the first reference, but the last info.inEvent = false; after QCoreApplication::postEvent(this, new QTimerEvent(id)); might still be toxic and neither solution solves that.