Replace the compareByteArrays functions, in src/core/crypto.js, with the isArrayEqual helper function

The `compareByteArrays` is first of all duplicated in multiple closures in the `src/core/crypto.js` file. Secondly, despite its name, it's also functionally equivalent to the now existing `isArrayEqual` helper function.

The `isArrayEqual` helper function is changed to use a standard `for`-loop, rather than `Array.prototype.every`, since that ought to be slightly more efficient given that we're now using it with (potentially) larger data.

src/shared/util.js

@@ -884,9 +884,12 @@ function isArrayEqual(arr1, arr2) {
   if (arr1.length !== arr2.length) {
     return false;
   }
-  return arr1.every(function (element, index) {
-    return element === arr2[index];
-  });
+  for (let i = 0, ii = arr1.length; i < ii; i++) {
+    if (arr1[i] !== arr2[i]) {
+      return false;
+    }
+  }
+  return true;
 }
 
 function getModificationDate(date = new Date()) {