This commit refactors the e2e tests in the following ways:
* bump the version of `bash_unit` to 1.7.2: the previous version was
from 2018;
* remove the unused `block` function;
* fix the order of `block_unitil_ready_by_name` and `check_ping`: we
should not attempt to interact with pods before they are considered
ready;
* extract the retry logic into a reusable function called `retry`; and
* retry the `check_adjacent` function for robustness.
Signed-off-by: Lucas Servén Marín <lserven@gmail.com>
9f088b87ee