remove gnu-gcc

we do not run this...

Author: nagisa

src/ci/github-actions/jobs.yml

@@ -147,9 +147,6 @@ pr:
     <<: *job-linux-4c
   - name: x86_64-gnu-miri
     <<: *job-linux-4c
-  - name: x86_64-gnu-gcc
-    doc_url: https://rustc-dev-guide.rust-lang.org/tests/codegen-backend-tests/cg_gcc.html
-    <<: *job-linux-4c
   - name: sbf-solana-solana
     continue_on_error: true
     env: