Fix dead link to the Ant task in faq.fml
Fix dead link to the Ant task in faq.fml

URL http://ant.apache.org/manual/OptionalTasks/junit.html is dead.  Use
up-to-date URL for documentation of Ant's JUnit task in file 'faq.fml'.
This is similar to commit 24dfdd76 (Fix dead link to the ant task in FAQ
(#1478), 2017-08-08).

junit-team/junit4,junit-team/junit4,junit-team/junit,junit-team/junit,junit-team/junit4,junit-team/junit