Fix flaky failure recovery assertions

[arhimondr]

Description

Depends on the timing of the request timeout failure injection a
task might fail either with the "Encountered too many errors talking to
a worker node" error message (when a failure happened to be injected before the
last request to get task results) or with the "Error closing remote buffer"
error message (when a failure happened to be injected after all requests
getting task results have already succeeded).

Is this change a fix, improvement, new feature, refactoring, or other?

Fix

Is this a change to the core query engine, a connector, client library, or the SPI interfaces? (be specific)

Tests

How would you describe this change to a non-technical end user or system administrator?

N/A

Related issues, pull requests, and links

#12151

Documentation

(x) No documentation is needed.
( ) Sufficient documentation is included in this PR.
( ) Documentation PR is available with #prnumber.
( ) Documentation issue #issuenumber is filed, and can be handled later.

Release notes

(x) No release notes entries required.
( ) Release notes entries required with the following suggested text:

# Section
* Fix some things. ({issue}`issuenumber`)