add some data to the repl init fail ex-info

Author: swannodette

src/main/clojure/cljs/repl.cljc

@@ -1214,7 +1214,9 @@
                          (flush))
                        (recur))))))))
          (catch Throwable t
-           (throw (ex-info "Unexpected error during REPL initialization" {} t)))
+           (throw
+             (ex-info "Unexpected error during REPL initialization"
+               {::error :init-failed} t)))
          (finally
            (reset! done? true)
            (-tear-down repl-env)))))))