Run test against all compilers for PRs

TODO

• Establish functional CI
• Document said CI
• Document repo workflow (no forks, developer access for lab participants)
• Add all lab participants as developers (Moved to #2 (closed))

Goal

This hopefully helps Paul judge whether a test is correct or not, as the results of the various compilers are directly visible.

Requirements

• Gitlab runner (I can offer mine, if a repo owner of the IPDSnelting/mjtests-tests gives me a token or you build your own)
• All groups need to work in the IPDSnelting repo and especially not in their own forks. They can work in their own branches and MR those, but they must not fork the project.

Runner requirements

I do not have access to Sebastian's docker image so I built my own:

FROM openjdk:17-bullseye

# Misc tools
RUN apt update && apt install unzip make git gradle jq -y

## Maven
RUN curl -L https://archive.apache.org/dist/maven/maven-3/3.8.3/binaries/apache-maven-3.8.3-bin.zip -o /maven.zip
RUN unzip /maven.zip -d /maven
RUN ln -s /maven/apache-maven-3.8.3/bin/mvn /bin

RUN git clone https://git.scc.kit.edu/IPDSnelting/mjtest.git /mjtest

RUN rm -rf /mjtest/tests

The CI config assumes the image is present locally (e.g. building it and adjusting the "pull-policy" of the gitlab runner) and is named mjtest.