No real changes, just remove an unneeded header dependency.

No real changes, just remove an unneeded header dependency.

There was some commented out code in (core) valgen.cpp file using
wxDatePickerCtrl (from adv library). Also comment out the inclusion of
wx/datectrl.h header as it's not needed as long as this code remains commented
out and creates an unexpected dependency of a core library file on an adv
library header.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66533 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775