[CI/tigron]: investigate file descriptor leak detection as a testing feature

### What is the problem you're trying to solve

Probably leverage `lsof -nP -p X` (or implement it in go)

### Describe the solution you'd like

Automatically fail a test if the test is leaking file descriptors.

Ideally, fail a test if the tested binary is leaking.

### Additional context

Note: evaluate #4013 as well.