SERVER-44793 Tag index_bounds_maxkey.js as 'requires_fcv_44'.

This tests behavior which was implemented under
SERVER-35921.

Author: dstorch

jstests/core/index_bounds_maxkey.js

@@ -1,5 +1,5 @@
 // Index bounds generation tests for MaxKey values.
-// @tags: [requires_non_retryable_writes, assumes_unsharded_collection]
+// @tags: [requires_non_retryable_writes, assumes_unsharded_collection, requires_fcv_44]
 (function() {
 "use strict";