tests: unit test to cause a problem in kmemleak

[RomanBelozerov]

We have the issue about the adding a new CI job for kernel with sanitizers and checkers. (See #23 and #2211). We have implemented memory check using lmemleak for each test from tempesta-test (-m option) and we have job for this. But this check may be unreliable because there is no warranty that test framework expects the result. (it can work differently for different VMs).

So we need a function or unit tests in TempestaFW that will 100% cause problem and we will be able to find it in python tests using kmemleak (-m option)