Reproduce the assertion by configuring a 'named' resolver with
'recursive-clients 10;' configuration option and running 20
queries is parallel.
Also tweak the 'ans2/ans.pl' to simulate a 50ms network latency
when qname starts with "latency". This makes sure that queries
running in parallel don't get served immediately, thus allowing
the configured recursive clients quota limitation to be activated.
(cherry picked from commit 4b52b0b4a9)
d6568bea7c