Preventing multiple connections from php subprocesses launched from php #167

This line in the default WordPress phpunit setup fires off a php subprocess: https://github.com/WordPress/wordpress-develop/blob/master/tests/phpunit/includes/bootstrap.php#L68

This causes multiple connections to xdebug. If you set a breakpoint on this line, the multiple connections will confuse the php-debug extension and the code wont go past that point.

There should be a configuration to set the maximum number of sessions, beyond which additional sessions get rejected. In this case, setting the maximum number of xdebug sessions to 1 should take care of this problem.