release-23.2: roachtest: make failure recovery independent

[blathers-crl]

Backport 1/1 commits from #119650 on behalf of @andrewbaptist.

/cc @cockroachdb/release

---

Previously, the multiple failures were started and finished
independently. This caused a problem if the ability to recover from one
failure depended on a different failure recovering first. To mitigate
this, recover each failure in a separate goroutine. This will allow the
"most important" failure to recover first so that the others can recover
if they depend on each other.

This is more important today while we don't recover from all the failure
modes that chaos implements. Specifically we don't handle partial
partitions fully with epoch leases.

Epic: none
Fixes: #119085
Fixes: #119347
Fixes: #119361
Fixes: #119454

Release note: None

---

Release justification: Test only change.

[blathers-crl]

Thanks for opening a backport.

Please check the backport criteria before merging:

• Backports should only be created for serious
  issues or test-only changes.
• Backports should not break backwards-compatibility.
• Backports should change as little code as possible.
• Backports should not change on-disk formats or node communication protocols.
• Backports should not add new functionality (except as defined
  here).
• Backports must not add, edit, or otherwise modify cluster versions; or add version gates.
• All backports must be reviewed by the owning areas TL and one additional
  TL. For more information as to how that review should be conducted, please consult the backport
  policy.

If your backport adds new functionality, please ensure that the following additional criteria are satisfied:

• There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
• The new functionality is additive-only and only runs for clusters which have specifically “opted in” to it (e.g. by a cluster setting).
• New code is protected by a conditional check that is trivial to verify and ensures that it only runs for opt-in clusters. State changes must be further protected such that nodes running old binaries will not be negatively impacted by the new state (with a mixed version test added).
• The PM and TL on the team that owns the changed code have signed off that the change obeys the above rules.
• Your backport must be accompanied by a post to the appropriate Slack
  channel (#db-backports-point-releases or #db-backports-XX-X-release) for awareness and discussion.

Also, please add a brief release justification to the body of your PR to justify this
backport.

[cockroach-teamcity]

This change is