Ensure that Forest and Lotus snapshots match byte-for-byte #3170

Issue summary

While restoring the --tipset flag for snapshot export in PR #3027, testing of the restored functionality revealed that there appears to be a regression that results in the Forest and Lotus snapshots no longer matching byte-for-byte. This was previously corrected in PR #2540, but the current mismatch may not be related to the walk_snapshot function. Investigate and ensure that both clients' snapshots match byte-for-byte.

Other information and links

May be fixed in #3173