Bug 1291473: set tiers explicitly; r=mshal

MozReview-Commit-ID: IPmiAWw5QEF

--HG--
extra : rebase_source : 709b81479f2702663b8ed808640997290127850b

taskcluster/ci/legacy/tasks/builds/dbg_linux64-asan.yml

@@ -26,5 +26,6 @@ task:
       machine:
         # see https://github.com/mozilla/treeherder/blob/master/ui/js/values.js
         platform: linux64
+      tier: 1
       collection:
         asan: true

taskcluster/ci/legacy/tasks/builds/dbg_linux64.yml

@@ -23,6 +23,7 @@ task:
       groupSymbol: tc
       groupName: Submitted by taskcluster
       symbol: B
+      tier: 1
       collection:
         debug: true
 

taskcluster/ci/legacy/tasks/builds/opt_linux64-asan.yml

@@ -26,5 +26,6 @@ task:
         # see https://github.com/mozilla/treeherder/blob/master/ui/js/values.js
         platform: linux64
       symbol: Bo
+      tier: 1
       collection:
         asan: true

taskcluster/ci/legacy/tasks/builds/opt_linux64.yml

@@ -19,4 +19,4 @@ task:
       groupSymbol: tc
       groupName: Submitted by taskcluster
       symbol: B
-
+      tier: 2