check that string passed to FromUTF8() is valid even in release build, this is safer; add a separate FromUTF8Unchecked() which can be used for maximal efficiency

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@54721 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/xml/xml.cpp

@@ -485,7 +485,7 @@ static wxString CharToString(wxMBConv *conv,
 #endif // !wxUSE_UNICODE
 
     wxUnusedVar(conv);
-    return wxString::FromUTF8(s, len);
+    return wxString::FromUTF8Unchecked(s, len);
 }
 
 // returns true if the given string contains only whitespaces