[lldb] vwprintw -> vw_printw in IOHandlerCursesGUI

`vwprintw` is (in theory) using the `arargs.h` va_list while `vw_printw` is
using the `stdarg.h` va_list. It seems these days they can be used
interchangeably but `vwprintw` is marked as deprecated.

lldb/source/Core/IOHandlerCursesGUI.cpp

@@ -461,7 +461,7 @@ public:
   void Printf(const char *format, ...) __attribute__((format(printf, 2, 3))) {
     va_list args;
     va_start(args, format);
-    vwprintw(m_window, format, args);
+    vw_printw(m_window, format, args);
     va_end(args);
   }