put flag check at the end of command chain in mingw-check-2

Author: Shourya742

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

@@ -27,9 +27,7 @@ COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
 ENV SCRIPT \
-        # The BOOTSTRAP_TRACING flag is added to verify whether the 
-        # bootstrap process compiles successfully with this flag enabled.
-        BOOTSTRAP_TRACING=1 python3 ../x.py check && \
+        python3 ../x.py check && \
         python3 ../x.py clippy ci && \
         python3 ../x.py test --stage 1 core alloc std test proc_macro && \
         python3 ../x.py doc --stage 0 bootstrap && \
@@ -38,4 +36,7 @@ ENV SCRIPT \
         RUSTDOCFLAGS=\"--document-private-items --document-hidden-items\" python3 ../x.py doc --stage 1 library && \
         mkdir -p /checkout/obj/staging/doc && \
         cp -r build/x86_64-unknown-linux-gnu/doc /checkout/obj/staging && \
-        RUSTDOCFLAGS=\"--document-private-items --document-hidden-items\" python3 ../x.py doc --stage 1 library/test
+        RUSTDOCFLAGS=\"--document-private-items --document-hidden-items\" python3 ../x.py doc --stage 1 library/test && \
+        # The BOOTSTRAP_TRACING flag is added to verify whether the 
+        # bootstrap process compiles successfully with this flag enabled.
+        BOOTSTRAP_TRACING=1 python3 ../x.py --help