Use wxDELETE() and wxDELETEA() when possible.

Use wxDELETE[A]() functions which automatically NULL out their arguments after
deleting them instead of doing it manually.

Closes #9685.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64656 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/strconv.cpp

@@ -3013,10 +3013,9 @@ wxCSConv& wxCSConv::operator=(const wxCSConv& conv)
 void wxCSConv::Clear()
 {
     free(m_name);
-    delete m_convReal;
+    wxDELETE(m_convReal);
 
     m_name = NULL;
-    m_convReal = NULL;
 }
 
 void wxCSConv::SetName(const char *charset)