Work around an unknown ArrayBuffer bug in iOS 14.5

In one Tabris.js application we ran into a case where an empty
ArrayBuffer was unexpectedly detached. That caused "Receiver is
detached" type error in `slice()` method.

Since we do not know for sure why and how that ArrayBuffer was happened
to be detached we implement a workaround to prevent this exception.

This issue was not reproducible in any lower version of iOS.

Change-Id: Id4216fdde4aa000ab3a4b8d996a588c0632d5297

Author: karolszafranski

src/tabris/util.js

@@ -175,7 +175,7 @@ export function isReadable(value) {
  */
 export function read(value) {
   if (value instanceof ArrayBuffer) {
-    return value.slice(0);
+    return value.byteLength === 0 ? new ArrayBuffer() : value.slice(0);
   }
   if (ArrayBuffer.isView(value)) {
     return value.buffer.slice(0);