CP-35266: remove some unused files to free disk space in CI (#548)

The disk being almost full was causing some tests to fail in CI.
This just deletes some stuff we don't use (like .NET and GHC)
before running the smoke tests.

Author: evan-cz

.github/workflows/golang-ci.yml

@@ -212,6 +212,28 @@ jobs:
       - name: Install dependencies in tests directory
         run: go -C tests mod tidy
 
+      # Free up disk space to prevent Docker overlay FS from exceeding 85%
+      - name: Free up disk space
+        run: |
+          echo "=== Cleaning up disk space ==="
+
+          # Remove Docker images and build cache
+          docker system prune -af --volumes
+
+          # Clean apt cache
+          sudo apt-get clean
+          sudo rm -rf /var/lib/apt/lists/*
+
+          # Remove large tools we don't need
+          # Android SDK, .NET, etc. are often pre-installed but unused
+          sudo rm -rf /usr/share/dotnet
+          sudo rm -rf /usr/local/lib/android
+          sudo rm -rf /opt/ghc
+
+          echo ""
+          echo "=== Disk Usage After Cleanup ==="
+          df -h / | tail -1
+
       # smoke tests hit alfa.
       - name: Run smoke tests
         run: GO="$(which go)" sudo -E make test-smoke