DAOS-19557 test: replace add_pool with self.get_pool

[daltonbohning]

• Replace test_utils_pool.py:add_pool with self.get_pool so there is only one pool method
• Do the same with add_pools
• Remove ior_test_base.py:create_pool
• Update tests to use self.get_pool
• Define ExecutableCommand.temp_exit_status_exception
  • Use it in self.remove_pool

Features: ior
Quick-functional: true
Allow-unstable-test: true

Steps for the author:

• Commit message follows the guidelines.
• Appropriate Features or Test-tag pragmas were used.
• Appropriate Functional Test Stages were run.
• At least two positive code reviews including at least one code owner from each category referenced in the PR.
• Testing is complete. If necessary, forced-landing label added and a reason added in a comment.

After all prior steps are complete:

• Gatekeeper requested (daos-gatekeeper added as a reviewer).

[github-actions]

Ticket title is 'ftest: consolidate self.get_pool and add_pool'
Status is 'In Progress'
https://daosio.atlassian.net/browse/DAOS-19557

[daosbuild3]

Test stage Functional on EL 9 completed with status FAILURE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net//job/daos-stack/job/daos/view/change-requests/job/PR-18954/1/execution/node/746/log

[daosbuild3]

Test stage Functional Cluster Box Medium Verbs Provider MD on SSD completed with status FAILURE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net//job/daos-stack/job/daos/view/change-requests/job/PR-18954/1/execution/node/977/log

[daosbuild3]

Test stage Functional on EL 9 completed with status FAILURE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net//job/daos-stack/job/daos/view/change-requests/job/PR-18954/2/execution/node/747/log

[daosbuild3]

Test stage Functional on EL 9 completed with status UNSTABLE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net/job/daos-stack/job/daos//view/change-requests/job/PR-18954/3/testReport/

[daosbuild3]

Test stage Functional Cluster Box Medium MD on SSD completed with status FAILURE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net//job/daos-stack/job/daos/view/change-requests/job/PR-18954/3/execution/node/983/log

[daosbuild3]

Test stage Functional Cluster Box Medium Verbs Provider MD on SSD completed with status FAILURE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net//job/daos-stack/job/daos/view/change-requests/job/PR-18954/3/execution/node/972/log