Revert "ci: Work around broken python UTF8 handling in the CI docker image"

This reverts commit 899d2607.

No longer necessary with the previous changes.

Reviewed-by: Eric Anholt <eric@anholt.net>
2 jobs for piglit-run in 6 minutes and 27 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Docker Image
passed #65745
debian-testing

00:05:36

 
  Build And Test
passed #65746
build-and-test

00:00:51