Allow code bundling of utility functions (#2586)

lib/utility.js

@@ -157,14 +157,10 @@ simd(true);
  * @private
  */
 module.exports = function (Sharp) {
-  [
-    cache,
-    concurrency,
-    counters,
-    simd
-  ].forEach(function (f) {
-    Sharp[f.name] = f;
-  });
+  Sharp.cache = cache;
+  Sharp.concurrency = concurrency;
+  Sharp.counters = counters;
+  Sharp.simd = simd;
   Sharp.format = format;
   Sharp.interpolators = interpolators;
   Sharp.versions = versions;