If we increase the remote screen size from the server in such a way that
it no longer fits the browser window, the browser will probably want to
show scrollbars. The same happens if you enable 'clipping' while the
remote is larger than the browser window. These scrollbars do, in turn,
decrease the available space in the browser window. This causes our
ResizeObserver to trigger.
If the resize observation triggers a requestRemoteResize() we will
overwrite the size and request a new one just because scrollbars have
appeared. We don't want that.
We can save the expected client size after resizing, and then compare
the current client size with the expected one. If there is no change
compared to the expected size, we shouldn't send the request.
Fixes issue #1616.