long-test failed on RHEL 8.0

Host: ec2-3-87-157-235.compute-1.amazonaws.com
Project: WiredTiger (develop)
Commit: diff: WT-8914 Add python testing for tiered storage (including S3) to pull request tests (#7669)

• Made `evergreen.yml` file changes to add extension testing to PR.
• Created new subset test `tiered-test-small` which runs just `test_tiered06.py` from tiered testing on the storage sources in PRs. | 18 Mar 22 00:13 UTC
  Evergreen Subscription: ; Evergreen Event:

Task Logs (long-test)