cached_filestorage fails on 2nd attempt under Ubuntu 20.04

[dimalit]

In unit tests, when running from github actions ("build and test skaled"), test 'cached_filestorage' succeeds from 1st attempt and fails on second one. Need to try it locally. See https://github.com/skalenetwork/skaled/actions/workflows/test.yml

Need to try to reproduce locally and find out what happened.

Logs:
2023-03-20T15:29:34.5603292Z /home/ubuntu/actions-runner/_work/skaled/skaled/test/unittests/libweb3jsonrpc/jsonrpc.cpp(2922): �[4;31;49mfatal error: in "JsonRpcSuite/FilestorageCacheSuite/cached_filestorage": critical check !boost::filesystem::exists( fixture.path ) has failed�