Fix wxSetCursorEvent handling
For compatibility with wxMSW, send event up the parent chain.
Properly handle setting the cursor for a wxSetCursorEvent, and don't overwrite the window cursor.
see #15801


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75821 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775