Speedup loader's __getArray (AssemblyScript#814)

Author: MaxGraey

lib/loader/index.js

@@ -199,7 +199,11 @@ function postInstantiate(baseModule, instance) {
 
   /** Reads (copies) the values of an array from the module's memory. */
   function __getArray(arr) {
-    return Array.from(__getArrayView(arr));
+    const input = __getArrayView(arr);
+    const len = input.length;
+    const out = new Array(len);
+    for (let i = 0; i < len; i++) out[i] = input[i];
+    return out;
   }
 
   baseModule.__getArray = __getArray;