Bug 1696041 - [ci] Remove 'fission-tier' from raptor.yml, r=perftest-reviewers,sparky

This change causes a slight change in the taskgraph. Essentially it changes the
optimization for some fission raptor tasks from 'skip-unless-expanded' to
'skip-unless-backstop'. This change happened because the
'apply_raptor_tier_optimization' transform did not take 'fission-tier' into
account. Now that 'fission-tier' has merged with 'tier', these tasks are being
modified by this transform. In my view this change is a desired outcome.

Differential Revision: https://phabricator.services.mozilla.com/D109664

taskcluster/ci/test/raptor.yml

@@ -66,7 +66,6 @@ job-defaults:
             default:
                 - .*
     tier: 2
-    fission-tier: 2
     virtualization: hardware
     mozharness:
         script: raptor_script.py
@@ -212,7 +211,10 @@ raptor-motionmark-animometer-firefox:
                             windows10-64-shippable-qr/opt: ["mozilla-central"]
                             default: []
             default: []
-    tier: 1
+    tier:
+        by-variant:
+            fission: 2
+            default: 1
     mozharness:
         extra-options:
             - --test=raptor-motionmark-animometer
@@ -234,7 +236,10 @@ raptor-webaudio-firefox:
     try-name: raptor-webaudio-firefox
     treeherder-symbol: Rap(wa)
     run-on-projects: []
-    tier: 1
+    tier:
+        by-variant:
+            fission: 2
+            default: 1
     mozharness:
         extra-options:
             - --test=raptor-webaudio
@@ -277,8 +282,10 @@ raptor-unity-webgl-firefox:
     try-name: raptor-unity-webgl-firefox
     treeherder-symbol: Rap(ugl)
     run-on-projects: []
-    fission-run-on-projects: []
-    tier: 3
+    tier:
+        by-variant:
+            fission: 2
+            default: 3
     mozharness:
         extra-options:
             - --test=raptor-unity-webgl
@@ -499,7 +506,10 @@ raptor-youtube-playback-v9-power-firefox:
             (linux|windows|macos)(?!.*shippable).*: []
             default: ["mozilla-central"]
     max-run-time: 2700
-    tier: 3
+    tier:
+        by-variant:
+            fission: 2
+            default: 3
     mozharness:
         extra-options:
             - --test=raptor-youtube-playback-v9
@@ -514,7 +524,10 @@ raptor-youtube-playback-h264-power-firefox:
             (linux|windows|macos)(?!.*shippable).*: []
             default: ["mozilla-central"]
     max-run-time: 2700
-    tier: 3
+    tier:
+        by-variant:
+            fission: 2
+            default: 3
     mozharness:
         extra-options:
             - --test=raptor-youtube-playback-h264
@@ -754,7 +767,10 @@ raptor-ares6-firefox-profiling:
     treeherder-symbol: Rap-Prof(ares6)
     run-on-projects: []
     max-run-time: 2500
-    tier: 3
+    tier:
+        by-variant:
+            fission: 2
+            default: 3
     mozharness:
         extra-options:
             - --test=raptor-ares6
@@ -766,7 +782,10 @@ raptor-jetstream2-firefox:
     try-name: raptor-jetstream2-firefox
     treeherder-symbol: Rap(js2)
     run-on-projects: []
-    tier: 3
+    tier:
+        by-variant:
+            fission: 2
+            default: 3
     max-run-time: 8000
     mozharness:
         extra-options:
@@ -781,7 +800,10 @@ raptor-jetstream2-firefox-profiling:
     treeherder-symbol: Rap-Prof(js2)
     run-on-projects: []
     max-run-time: 8000
-    tier: 3
+    tier:
+        by-variant:
+            fission: 2
+            default: 3
     mozharness:
         extra-options:
             - --test=raptor-jetstream2