gitlab-ci: Share dEQP build process between x86 & ARM test image scripts

See https://gitlab.freedesktop.org/mesa/mesa/issues/2056

v2:
* Rename .gitlab-ci/deqp-build.sh => .gitlab-ci/build-deqp.sh
  (Eric Anholt)

Reviewed-by: Eric Anholt <eric@anholt.net>
4 files changed