Identify and fix issue in functional_tests that causes this process's memory to grow

Eventing CI Run encounters failure once in a while. Snippet from the logs included below:
http://ci-eventing.northscale.in/eventing-18.09.2022-09.42.fail.html

signal: killed
FAIL github.com/couchbase/eventing/tests/functional_tests 9740.047s

dmesg has the following:
[45822.125037] Out of memory: Kill process 2209 (functional_test) score 694 or sacrifice child
[45822.136380] Killed process 2209 (functional_test) total-vm:15132244kB, anon-rss:10463260kB, file-rss:0kB, shmem-rss:0kB
[45825.856240] oom_reaper: reaped process 2209 (functional_test), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

This issue could be due to a memory leak in functional_tests that causes the size to keep increasing and eventually get killed.

Need to identify / fix.