Move XTextField Java tests to C++ for ScEditFieldObj_Header (formerly
ScHeaderFieldObj).

Change-Id: I36b723945d9306720846b4a4e2d3eaddb1a1c063
Reviewed-on: https://gerrit.libreoffice.org/70841
Tested-by: Jenkins
Reviewed-by: Jens Carl <j.carl43@gmx.de>