Add a way to export offset used by the fuzzer

[0pendev]

Lots of fuzzing harness expect to be run against a corpus and not a dictionary.
When that is the case absolution can get it the way because the offset used by absolution to fill the global states are not publicly exposed.
A developper would need to manually go through the generated fuzzer.c wich is not ideal.

We could add an export of those offset with a basic format like how we export redefinitions

@N3ur0sis