feat: support ARMv6 glibc upgrade bundles

docker/Dockerfile.upgrade-bundle-armv6-glibc

@@ -0,0 +1,13 @@
+# An immutable digest of the CI-only ARM1176 validator, built in the same run.
+ARG BASE_IMAGE
+FROM ${BASE_IMAGE} AS bundle
+ARG BASE_IMAGE
+ENV QL_BUNDLE_BASE_IMAGE=${BASE_IMAGE}
+RUN ulimit -c 0; armv6-run /bin/bash -ec \
+    'node --jitless /ql/scripts/build-upgrade-bundle.cjs /ql /out; \
+     for archive in /out/*.tar.gz; do \
+       node /ql/shell/install-bundle.cjs --root /tmp/ql-bundle-offline-smoke --file "$archive" --install; \
+       rm -rf /tmp/ql-bundle-offline-smoke; \
+     done'
+FROM scratch
+COPY --from=bundle /armv6/out/ /