Performance tests

[Totktonada]

It would be nice to add several benchmarks into the repository to ease performance evaluation during development.

What I'm interested about:

• Point Select (as some kind of baseline).
• Large Select (to look on msgpack decoder performance).
• Replace (not really about connector's performance, rather about tarantool, but anyway interesting, whether there will be a noticeable difference from a point Select).

Consider snippets from tarantool/tarantool#3603.

Let's leave regular performance tracking and the relevant infrastructure out of context here.