Windows: Prevent platform thread from deadlocking during window resize

[abnemo]

Fixes flutter/flutter#77034

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[jnschulze]

I was looking at the same issue a couple of days ago and assumed that it would only occur if FlutterWindowsView::OnWindowSizeChanged gets invoked before the first frame gets rendered (there was a similar issue on macOS: #22457).

However, I realized that it AFAICT only occurs when attempting to resize the window programmatically using SetWindowPos or MoveWindow.

I haven't found the root cause yet but I think having a timeout for the resize condition variable is a viable safety net.
It's definitely better than risking to block the platform thread forever.

[jnschulze]

I just tested it with the example of the linked issue (flutter/flutter#77034) and can confirm that the window gets properly moved and resized without freezing the app.

[tilongzs]

Great, thanks a lot for the fix.

[cbracken]

Nice -- Thanks!