disable cg_gcc tests

Author: saethlin

src/ci/github-actions/jobs.yml

@@ -98,7 +98,6 @@ pr:
     <<: *job-linux-4c
   - image: x86_64-gnu-llvm-18
     env:
-      ENABLE_GCC_CODEGEN: "1"
       # We are adding (temporarily) a dummy commit on the compiler
       READ_ONLY_SRC: "0"
       DOCKER_SCRIPT: x86_64-gnu-llvm.sh