DAOS-16257 mercury: Test addition of flush before ep close.

[jgmoore-or]

PR-repos: mercury@PR-126:3
Test-provider: ucx+ud_x
Skip-build-leap15-icc: true
Skip-build-el8-gcc: true
Skip-func-test-vm: true
Skip-unit-tests: true
Skip-func-hw-test-medium-verbs-provider: true
Skip-func-hw-test-medium-ucx-provider: false

Required-githooks: true

Before requesting gatekeeper:

• Two review approvals and any prior change requests have been resolved.
• Testing is complete and all tests passed or there is a reason documented in the PR why it should be force landed and forced-landing tag is set.
• Features: (or Test-tag*) commit pragma was used or there is a reason documented that there are no appropriate tags for this PR.
• Commit messages follows the guidelines outlined here.
• Any tests skipped by the ticket being addressed have been run and passed in the PR.

Gatekeeper:

• You are the appropriate gatekeeper to be landing the patch.
• The PR has 2 reviews by people familiar with the code, including appropriate owners.
• Githooks were used. If not, request that user install them and check copyright dates.
• Checkpatch issues are resolved. Pay particular attention to ones that will show up on future PRs.
• All builds have passed. Check non-required builds for any new compiler warnings.
• Sufficient testing is done. Check feature pragmas and test tags and that tests skipped for the ticket are run and now pass with the changes.
• If applicable, the PR has addressed any potential version compatibility issues.
• Check the target branch. If it is master branch, should the PR go to a feature branch? If it is a release branch, does it have merge approval in the JIRA ticket.
• Extra checks if forced landing is requested
  • Review comments are sufficiently resolved, particularly by prior reviewers that requested changes.
  • No new NLT or valgrind warnings. Check the classic view.
  • Quick-build or Quick-functional is not used.
• Fix the commit message upon landing. Check the standard here. Edit it to create a single commit. If necessary, ask submitter for a new summary.

[github-actions]

Ticket title is 'datamover/copy_procs.py:DmvrCopyProcs.test_copy_procs - dcp Segmentation fault: address not mapped to object at address 0xcc000000ca'
Status is 'In Progress'
Labels: '2.6.0rc2,2.6.0rc3,2.6.1rc1,2.6.1rc2,2.6.1rc3,2.7.101tb,daily_test,ucx_provider'
https://daosio.atlassian.net/browse/DAOS-16257

[daosbuild1]

Test stage Functional Hardware Medium completed with status UNSTABLE. https://build.hpdd.intel.com/job/daos-stack/job/daos//view/change-requests/job/PR-15631/1/testReport/

[daosbuild1]

Test stage Functional Hardware Medium completed with status FAILURE. https://build.hpdd.intel.com//job/daos-stack/job/daos/view/change-requests/job/PR-15631/2/execution/node/965/log