Revert "DAOS-18425 rebuild: coalesce tasks for multi-rank operations …

[kccain]

…(#17382)"

This reverts commit 4f86470.

Test-tag: test_continuous_after_stop
Test-repeat: 10

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 'interactive rebuild: "dmg system rebuild stop" not working in case of rank reintegration'
Status is 'In Review'
Labels: 'Rebuild,test_2.8'
Job should run at elevated priority (1)
https://daosio.atlassian.net/browse/DAOS-18425

[daosbuild3]

Test stage Functional Hardware 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-17720/4/execution/node/1229/log