pool: Fix data race in AIO tests

GitHub action runs tests with '-race' flag. This makes subtests run in
parallel. Previously, some subtests were dependent from each other:
 - eACL must be set after the container is created only;
 - object must be downloaded/delete only after upload only;
 - object download must expect success before the removal only;
 - any object tests must be performed before the container removal only.

This inlines dependent subtests into the superior one in a correct order
(it was correct if tests weren't run in parallel).

Refs #644.

Signed-off-by: Leonard Lyubich <[email protected]>