Revert "[tests] Use amd64 with Python 3.5"
Revert "[tests] Use amd64 with Python 3.5"

This reverts commit 5531419f235ef8ce7ed5d465d4f0dc04cb1a0ae1.

Reason for revert: Setting does not work in this way

Change-Id: I7b20099ee55bb7a95ca92cdedde4744ba0510c9e

wikimedia/pywikibot-core,wikimedia/pywikibot-core