Remove unnecessary IsRadioButton().

Replace m_blockEvent with g_signal_handlers_block().
Remove wxRadioButton::DoGetBestSize(), it just calls the base.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@51427 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/window.h

@@ -237,9 +237,6 @@ public:
     // is this window transparent for the mouse events (as wxStaticBox is)?
     virtual bool IsTransparentForMouse() const { return false; }
 
-    // is this a radiobutton (used by radiobutton code itself only)?
-    virtual bool IsRadioButton() const { return false; }
-
     // Common scroll event handling code for wxWindow and wxScrollBar
     wxEventType GetScrollEventType(GtkRange* range);