Disable default aggregated report. Reactivate auto-validation of reports against base branch. (#6939)
Disable default aggregated report. Reactivate auto-validation of reports against base branch. (#6939)

Following #6934, this PR finalize two things, as explained in #6934:

disable the default aggregated report
validate linux and windows reports against the PR base branch
stweil/letsencrypt,letsencrypt/letsencrypt,letsencrypt/letsencrypt,lmcro/letsencrypt,stweil/letsencrypt,lmcro/letsencrypt