VSE has three mouse cursors defined, WM_CURSOR_LEFT_HANDLE,
WM_CURSOR_RIGHT_HANDLE, and WM_CURSOR_BOTH_HANDLES that are currently
always using our default cursor format. This format works on all
platforms but does not support multiple sizes or antialiasing. This
PR makes these use custom cursors (created by Pablo Vazquez) on the
Windows platform.
Pull Request: https://projects.blender.org/blender/blender/pulls/125252