Reduce CI coverage for debugging, DON'T MERGE THIS TO MASTER!

.gitlab-ci.yml

@@ -8,30 +8,7 @@ before_script:
   - duneci-install-module https://gitlab.dune-project.org/core/dune-istl.git
   - duneci-install-module https://gitlab.dune-project.org/staging/dune-typetree.git
 
-debian:10  gcc:c++17:
-  image: duneci/base:10
-  script: duneci-standard-test
-  variables: {DUNECI_OPTS: /duneci/opts.gcc.c++17}
-  tags: [duneci]
-
-debian:9--gcc:
-  image: duneci/base:9
-  script: duneci-standard-test
-  tags: [duneci]
-
-debian:9--clang:
-  image: duneci/base:9
-  script: duneci-standard-test
-  variables: {DUNECI_OPTS: /duneci/opts.clang}
-  tags: [duneci]
-
 ubuntu:16.04--gcc:
   image: duneci/base:16.04
   script: duneci-standard-test
   tags: [duneci]
-
-ubuntu:16.04--clang:
-  image: duneci/base:16.04
-  script: duneci-standard-test
-  variables: {DUNECI_OPTS: /duneci/opts.clang}
-  tags: [duneci]