Tests: Make XML based optimization tests work with Python3 lxml properly.
Tests: Make XML based optimization tests work with Python3 lxml properly.

wfxiang08/Nuitka,wfxiang08/Nuitka,wfxiang08/Nuitka,tempbottle/Nuitka,kayhayen/Nuitka,kayhayen/Nuitka,kayhayen/Nuitka,tempbottle/Nuitka,tempbottle/Nuitka,wfxiang08/Nuitka,kayhayen/Nuitka,tempbottle/Nuitka