## Problem
The test is flaky: WAL in remote storage appears to be corrupted. One of
hypotheses so far is that corruption is the result of local fs
implementation being non atomic, and safekeepers may concurrently PUT
the same segment. That's dubious though because by looking at local_fs
impl I'd expect then early EOF on segment read rather then observed
zeros in test failures, but other directions seem even less probable.
## Summary of changes
Let's add s3 backend as well and see if it is also flaky. Also add some
more logging around segments uploads.
ref https://github.com/neondatabase/neon/issues/10761
98e18e9a54