Check validity of wxSizerFlags::Border() direction parameter.

Catch the misguided attempts to pass the size of the border as the first
parameter of the Border(direction, size) overload.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72434 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/sizer.h

@@ -125,6 +125,10 @@ public:
 
     wxSizerFlags& Border(int direction, int borderInPixels)
     {
+        wxCHECK_MSG( !(direction & ~wxALL), *this,
+                     wxS("direction must be a combination of wxDirection enum "
+                         "values.") );
+
         m_flags &= ~wxALL;
         m_flags |= direction;