`runtime/lib/query/Join.php:540` gives warnings in PHP7.4

[michalmagic42]

Issue: runtime/lib/query/Join.php:540 gives warnings in PHP7.4

The reason is that the implode() method is used against standard:
$joinCondition = sprintf('(%s)', implode($conditions, ' AND '));

For historical reasons, the implode() function supports passing the $glue and $pieces parameters in reverse order from the documented order of arguments. This is inconsistent and makes the argument handling non-standard.

Fix: change the line runtime/lib/query/Join.php:540
From: $joinCondition = sprintf('(%s)', implode($conditions, ' AND '));
To: $joinCondition = sprintf('(%s)', implode(' AND ', $conditions));