Add check for memory leaks to CI

[ghost]

A check for memory leaks can be added to CI in order to detect leaks caused by native dependencies. It can be done in a way similar to how it was added to quick-js crate.

[MOZGIII]

I like this, even though we use rust, it's good to have extra certainty that memory leaks are nonexistent.
Valgrind is a solid solution, there's also Dr. Memory. We probably should compare the two and figure out which one we like more. I used both in the past, and both are great.

[binarylogic]

Sounds good! @MOZGIII I've assigned this to you as part of your reliability / test harness work. We're in no rush, so feel free to work on this in the order you see fit.

[binarylogic]

@MOZGIII unless you think this is a very valuable and high priority feature I'd like to take it out of this project.

[MOZGIII]

Yes, let's leave it out for now.