run x check --stage 0 on CI

Signed-off-by: onur-ozkan <work@onurozkan.dev>

Author: onur-ozkan

src/ci/docker/host-x86_64/mingw-check-2/Dockerfile

@@ -27,6 +27,7 @@ COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
 ENV SCRIPT \
+        python3 ../x.py check --stage 0 && \
         python3 ../x.py clippy ci && \
         python3 ../x.py test --stage 1 core alloc std test proc_macro && \
         # Build both public and internal documentation.