community/clojure: allow 32-bit architectures (with OpenJDK 8 LTS)

Clojure actually requires openjdk version 8 as a minimum (https://clojure.org/releases/downloads#_java_compatibility), and that is still a supported LTS release.

Incidentally that's the last version with official 32-bit support, and the only version available in the Alpine repos for 32-bit architectures.

All in all, it makes sense to align the arch field for openjdk8 and clojure.