Check all tier 1 targets in PR CI

Author: ChrisDenton

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

@@ -42,6 +42,8 @@ ENV RUN_CHECK_WITH_PARALLEL_QUERIES 1
 
 ENV SCRIPT python3 ../x.py --stage 2 test src/tools/expand-yaml-anchors && \
            python3 ../x.py check --target=i686-pc-windows-gnu --host=i686-pc-windows-gnu && \
+           # check library crates on all tier 1 targets
+           python3 ../x.py check core alloc std --stage 0 --target=aarch64-unknown-linux-gnu,i686-pc-windows-msvc,i686-unknown-linux-gnu,x86_64-apple-darwin,x86_64-pc-windows-gnu,x86_64-pc-windows-msvc,x86_64-unknown-linux-gnu && \
            python3 ../x.py clippy compiler -Aclippy::all -Dclippy::correctness && \
            python3 ../x.py build --stage 0 src/tools/build-manifest && \
            python3 ../x.py test --stage 0 src/tools/compiletest && \