Use 4-core runner for the alt job

Signed-off-by: Jakub Beránek <[email protected]>

Author: Kobzol

src/ci/github-actions/jobs.yml

@@ -246,7 +246,7 @@ auto:
       IMAGE: dist-x86_64-linux
       CODEGEN_BACKENDS: llvm,cranelift
       DOCKER_SCRIPT: dist-alt.sh
-    <<: *job-linux-16c
+    <<: *job-linux-4c
 
   - name: dist-x86_64-musl
     env: