Manually test new opcode on LIGO

Formal test is somehow hard to write in OCaml and so I recommend a shell based smoke test.

After compile the custom ligo with custom Tezos, then run

ligo compile-expression "$(cat src/test/contracts/level_lock.ligo)" -s pascaligo

and you'll see your opcode is generated from ligo compiler.

It's good to use https://ide.ligolang.org/ as a stable compiler