Bug 1286075: use the default gecko-b-* workerType for all haz builds; r=sfink

MozReview-Commit-ID: 1d2w3rhb0qj

--HG--
extra : rebase_source : 8332496948570c59c2b5f2216a61886acf7faa67

taskcluster/ci/hazard/kind.yml

@@ -78,7 +78,6 @@ jobs:
             tier: 3
         run-on-projects:
             - try
-        worker-type: aws-provisioner-v1/mulet-debug  # TODO (taskdiff): change to default
         worker:
             docker-image: {in-tree: builder}
         run: