Summary
Add mongod logs to the artifacts saved by the many-collection-test

Motivation

• Does this affect any team outside of WT?
  No

• How likely is it that this use case or problem will occur?
  Always happen - we never save these logs

• If the problem does occur, what are the consequences and how severe are they?
  If the test fails, we lack enough information to diagnose failures, because we are not saving the logs.

• Is this issue urgent?
  Not urgent, but will help any future bugs seen through many-collection-test

Acceptance Criteria (Definition of Done)
When a test run of many-collection-test will provide a means to download the mongod logs

• Testing
  Unit testing - Run the test, confirm that you can download the mongod logs

• Documentation update
  No update required