Fix flaky blocks-add-node test

[nkryuchkov]

Motivation

Closes #2222

Changes

• Fix flaky blocks-add-node test

Test Plan

• System tests

TODO

• Fix flaky blocks-add-node test
• Finish created todo's
• Document changes

[noamnelke]

@nkryuchkov I saw you reformatted a few files - I'm generally not against this, but at this point in time it may cause avoidable conflicts with other PRs, so I suggest reverting those changes and possibly making them in a separate PR after we've mostly emptied our PR queue.

Only the following files should be part of this PR:

tests/block_atx/add_node/test_blocks_add_node.py
tests/queries.py
tests/utils.py

[nkryuchkov]

@noamnelke Thanks, I agree.

[nkryuchkov]

Superseded by #2239