Remove display information caching from MSW wxDisplay implementation.

Remove display information caching from MSW wxDisplay implementation.

Don't cache display rectangle and client rectangle as they can both change
during the program lifetime (especially the latter which changes whenever
taskbar is moved or shown/hidden) and retrieving them every time they're
needed doesn't seem to be a problem performance-wise anyhow.

We still cache the list of all the monitors, ideally we'd refresh it when we
receive a notification about a display being [dis]connected.

Closes #4582.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65555 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775