Define a metric to track ZK ASM cycles used for WASM opcodes

[aborg-dev]

As a part of work in Stage 2 it would be useful to identify performance metrics that we should aim to improve.
One such metric might be a number of ZK ASM cycles that each WASM opcode uses.
We currently have a crude way to measure it by taking the total number of cycles spent in the spec test for a specific opcode and dividing it by the number of tests.

This metric has a few deficiencies:

• It includes a constant overhead for creating ZK ASM program
• The number of cycles might vary based on the input to the instruction (e.g. due to optimizations with immediate values)

We need to address these efficiencies and start tracking this metric continuously.