CLJS-675: QuickStart example not working properly

Advanced compilation will fail if the output directory does not
exist. Make output directory before writing constants_table.js to
disk.

This error does not occur when compiling with lein-cljsbuild which
makes the output directory before calling build.

src/clj/cljs/compiler.clj

@@ -1025,6 +1025,7 @@
       (emits ";\n"))))
 
 (defn emit-constants-table-to-file [table dest]
+  (io/make-parents dest)
   (with-open [out ^java.io.Writer (io/make-writer dest {})]
     (binding [*out* out]
       (emit-constants-table table))))