Attempt to capture a core dump from OpenJ9

.github/workflows/ci.yml

@@ -400,10 +400,28 @@ jobs:
           distribution: 'adopt-openj9'
           java-version: '17'
           cache: 'maven'
+
+      - name: Set cores to get stored in /cores
+        run: |
+          sudo mkdir /cores
+          sudo chmod 777 /cores
+          # Core filenames will be of the form executable.pid.timestamp:
+          sudo bash -c 'echo "/cores/%e.%p.%t" > /proc/sys/kernel/core_pattern'
+
       - name: bootstrap
         run: mvn -Pbootstrap clean package
+
       - name: bundle install
-        run: bin/jruby --dev -S bundle install
+        run: |
+          ulimit -c unlimited
+          bin/jruby --dev -S bundle install
+
+      - uses: actions/upload-artifact@v3
+        if: ${{ failure() }}  # Run only if something went wrong
+        with:
+          name: cores
+          path: /cores
+
       - name: test profile
         run: "tool/maven-ci-script.sh"
         env: