Fuzz against a naive gas metering model

[pepyakin]

We can implement a naive model of gas metering that doesn't try to minimize the number of gas metering statements and collary is going to be very simple.

Then we can try to generate random wasm binaries, process them with either of models and then compare the amount of consumed gas of each.

For generation of random cases we can use binaryen's translate-to-fuzz.