Previously, the following series of steps would leave the window at
full-size on Windows:

- Open a JUCE Window
- Maximise it
- Minimise it
- Click the maximise button

The expected behaviour is that the window should return to its initial
size and position, but instead the window still fills the screen.

This issue wasn't present on Ubuntu/Unity because minimising does not
invoke ComponentPeer::handleMovedOrResized on that platform. It was not
present on macOS because the system is responsible for restoring the
previous window size on that platform.