New spurious GitLab CI errors to address

[Zimmi48]

• https://gitlab.com/coq/coq/-/jobs/163235497

  Cloning into '/builds/coq/coq'...
  fatal: unable to access 'https://gitlab-ci-token:xxxxxxxxxxxxxxxxxxxx@gitlab.com/coq/coq.git/': The requested URL returned error: 500
  /bin/bash: line 80: cd: /builds/coq/coq: No such file or directory
  ERROR: Job failed: exit code 1
  

• https://gitlab.com/coq/coq/-/jobs/163235488

  Pulling docker image gitlab/gitlab-runner-helper:x86_64-35e8515d ...
  ERROR: Job failed: execution took longer than 4h0m0s seconds
  

• https://gitlab.com/coq/coq/-/jobs/163235500

  Pulling docker image gitlab/gitlab-runner-helper:x86_64-7a7b8375 ...
  ERROR: Job failed: canceled
  

[Zimmi48]

fatal: remote origin already exists.
fatal: unable to access 'https://gitlab-ci-token:[MASKED]@gitlab.com/coq/coq.git/': OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to gitlab.com:443 

(https://gitlab.com/coq/coq/-/jobs/203836217 and https://gitlab.com/coq/coq/-/jobs/203836211)