Run dist verification with jruby-dist

In docker-library/official-images#20939 we discovered that the
jruby-dist artifacts were not including RubyGems extension stubs
needed for libraries like syslog to load. This change modifies our
verification process to attempt to run from the dist archive and
to load problematic standard libraries to hopefully catch issues
like this in the future.

Author: headius

.github/workflows/dist-verification-ci.yml

@@ -0,0 +1,83 @@
+name: Dist Verification CI
+
+on: [push, pull_request]
+
+env:
+  JAVA_OPTS: '-XX:+TieredCompilation -XX:TieredStopAtLevel=1 -Xms60M -Xmx1G -XX:InitialCodeCacheSize=40M -XX:ReservedCodeCacheSize=120M'
+
+permissions:
+  contents: read
+
+jobs:
+  build-dist:
+
+    strategy:
+      matrix:
+        java-version: ['21']
+      fail-fast: false
+
+    runs-on: ubuntu-latest
+
+    name: Build JRuby dist archive
+
+    steps:
+      - name: checkout
+        uses: actions/checkout@v3
+      - name: set up java 21
+        uses: actions/setup-java@v3
+        with:
+          distribution: 'zulu'
+          java-version: 21
+          cache: 'maven'
+      - name: build dist archive
+        run: |
+          mvn -ntp clean package -Pdist
+          mv maven/jruby-dist/target/jruby-dist*-bin.tar.gz jruby-dist-bin.tar.gz
+      - name: cache dist
+        uses: actions/upload-artifact@v4
+        with:
+          name: jruby-dist
+          path: jruby-dist-bin.tar.gz
+          retention-days: 1
+
+  rails-verification:
+
+    needs: build-dist
+
+    strategy:
+      matrix:
+        java-version: ['21', '25']
+        runs-on: [windows-latest, macos-latest, ubuntu-latest]
+      fail-fast: false
+
+    runs-on: ${{ matrix.runs-on }}
+
+    name: dist verification on ${{ matrix.runs-on }} (Java ${{ matrix.java-version }})
+
+    steps:
+      - name: checkout
+        uses: actions/checkout@v3
+        with:
+          path: jruby-src
+      - name: set up java ${{ matrix.java-version }}
+        uses: actions/setup-java@v3
+        with:
+          distribution: 'zulu'
+          java-version: ${{ matrix.java-version }}
+      - name: download cached dist
+        uses: actions/download-artifact@v5
+        with:
+          name: jruby-dist
+      - name: unpack dist
+        run: tar xzf jruby-dist-bin.tar.gz --strip-components=1
+      - name: dist verification (Windows)
+        if: matrix.runs-on == 'windows-latest'
+        run: echo "${{ github.workspace }}\bin" | Out-File -Append -FilePath $env:GITHUB_PATH -Encoding utf8
+      - name: set up dist path (Unix)
+        if: matrix.runs-on != 'windows-latest'
+        run: echo "$(pwd)/bin" >> $GITHUB_PATH
+      - name: rails verification
+        run: jruby jruby-src/tool/rails_runner
+      - name: syslog verification (Unix)
+        if: matrix.runs-on != 'windows-latest'
+        run: jruby -rsyslog -e 1