Enable ESI processing for the Testing carrier range

The Enable-ESI response header from MediaWiki indicates there are
ESI directives in the body. The X-FORCE-ESI request header suggests
to MediaWiki to use ESI.

Change-Id: I317d5b637d63d371a897c7853d4e887389baa334
Disable X-FORCE-ESI for now

We need to wait until all frontends have ESI enabled.

Change-Id: I5e128f28ee7e24565f839dff7ef949cc9eb725c4