Tests/SCORU: Generate regressions for dissections

Context

The computing of dissections by the rollup node is a sensitive matter, as an error in a dissection step means that the opponent can refute our step and produce a valid proof.

This MR introduces regression traces for the dissections computed in the tezt tests so that we make sure that future changes in how we compute dissections do not change the results. ⚠ These regressions traces are only for the arith PVM as the state of the WASM PVM depends on the timestamps of blocks (due to info per level messages).

This MR is a prerequisite of !6948 (merged) (which indeed optimizes the dissection computation).
Depends on !8059 (merged).

Manually testing the MR

dune exec tezt/tests/main.exe -- -f sc_rollup.ml refutation