Adapt 0 A.D. to SpiderMonkey ESR 102

This follows the migration guide at:
https://github.com/mozilla-spidermonkey/spidermonkey-embedding-examples

Based on patch by: wraitii
Differential Revision: https://code.wildfiregames.com/D5002

source/ps/scripting/JSInterface_VFS.cpp

@@ -98,7 +98,7 @@ struct BuildDirEntListState
 		filename_array(rq.cx),
 		cur_idx(0)
 	{
-		filename_array = JS::NewArrayObject(rq.cx, JS::HandleValueArray::empty());
+		filename_array = JS::NewArrayObject(rq.cx, 0);
 	}
 };