11.4 JSON functions not interuptable

11.4 json functions need to be killable/timeout.

Functions added in 11.4:

• JSON_ARRAY_INTERSECT
• JSON_OBJECT_FILTER_KEYS
• JSON_OBJECT_TO_ARRAY
• JSON_KEY_VALUE
• JSON_SCHEMA_VALIDE

Like MDEV-28404 they need:

• je.killed_ptr assignment after json_scan_start where the is a function to json_scan_next used within the Item
• Remove check_killed() if present - handled by report_json_error.
• JSON_DO_PAUSE_EXECUTION(thd, 0.0002); in Item_function::val*
• json library functions to end up in report_json_error(js, &je, 0); immediately after error, and return null.
• add to func_json_notembedded.test - ensure result file is the timeout error.