.gitlab-ci.yml: make 'test-compiler' job more present

See #3310.
9 jobs for feature-a/1409-export-the-best-v-d-j in 20 minutes and 1 second (queued for 2 seconds)
Status Job ID Name Coverage
  Test Tools
passed #140357
test_tools

00:00:05

 
  Test Unit
passed #140358
test_algo_unit

00:03:28

 
  Test Functional
passed #140359
test_algo_should

00:11:09

manual #140360
several-compilers allowed to fail manual
test_various_compilers
 
  Test Shouldvdj
canceled #140361
test_algo_shouldvdj

00:05:18

 
  Coverage
canceled #140362
algo_coverage

 
  Prepare Release
canceled #140363
allowed to fail manual
prepare_release

 
  Valgrind Unit
canceled #140364
valgrind
algo_valgrind_unit

 
  Valgrind Functional
canceled #140365
valgrind allowed to fail manual
algo_valgrind_functional