test: add test filter for box.snapshot

Added test-run filter on box.snapshot error message:

  'Invalid VYLOG file: Slice [0-9]+ deleted but not registered'

to avoid of printing changing data in results file to be able to use
its checksums in fragile list of test-run to rerun it as flaky issue.
Also added checksums to fragile list for the following tests:

  vinyl/iterator.test.lua                       gh-5141
  vinyl/snapshot.test.lua                       gh-4984

Needed for #5141
Needed for #4984