Wasm: fix typo pp_state

Context

A state called Start was added then removed. When it was removed, it was replaced in the execution loop by Snapshot. The test helper pp_state was not updated at the time. pp_state is used in the verbose mode by the benchmark tool to output the final state of a computation. Start doesn't reflect the effective state Snapshot.

This MR simply correct this mistake.

Manually testing the MR

Nothing changes outside of debug.

Checklist

• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR