Memory-leak happens during fuzzing test

[baltsers]

Describe the bug
memory continues to grow during testing, see log.

(base) root@ubuntu:/home/wen/git/polyfuzz/aubio# ./run.sh case-abnormal
[1] Thu May 19 23:31:13 PDT 2022: memory percentage: 0.1
[2] Thu May 19 23:31:43 PDT 2022: memory percentage: 1.9
[3] Thu May 19 23:32:13 PDT 2022: memory percentage: 3.0
[4] Thu May 19 23:32:43 PDT 2022: memory percentage: 4.1
[5] Thu May 19 23:33:13 PDT 2022: memory percentage: 5.2
[6] Thu May 19 23:33:43 PDT 2022: memory percentage: 6.3
[7] Thu May 19 23:34:13 PDT 2022: memory percentage: 7.4
[8] Thu May 19 23:34:43 PDT 2022: memory percentage: 8.5
[9] Thu May 19 23:35:13 PDT 2022: memory percentage: 9.6
[10] Thu May 19 23:35:43 PDT 2022: memory percentage: 10.6

To Reproduce

run the command: ./run.sh case-abnormal
python-script

**** Environment ****
Python3.8 & Ubuntu18.04
Aubio-version: the main branch

Expected behavior
the memory usage should not continue to increase