Fix showing back hidden columns and rows in wxGrid.

While we don't support auto-sizing of the hidden columns and rows, we need to
still show them back when SetColSize() or SetRowSize() is called with -1
(a.k.a. wxGRID_AUTOSIZE) argument.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73848 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775