Preserve value when changing range of inverted wxSlider in wxMSW.

Preserve value when changing range of inverted wxSlider in wxMSW.

The logical value of wxSlider was changed when its range was changed in wxMSW
if the slider had wxSL_INVERSE style because the logical value was actually
computed using the range and the actual physical control value and we forgot
to update the latter when changing the range.

Do update it now in SetRange() to fix this.

Also add unit tests checking for this and, more generally, for other
operations with inversed sliders.

Closes #12765.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66368 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775