Bug 1503299 - Run Android 7.0 x86 crashtests and mochitest-clipboard as tier 1; r=me,a=test-only

--HG--
extra : rebase_source : d0f1241fcad7d2254dadc8ecad0f36fc80274695

taskcluster/ci/test/mochitest.yml

@@ -212,10 +212,6 @@ mochitest-clipboard:
                     - --test-suite=mochitest-plain-clipboard
                 default:
                     - --mochitest-suite=plain-clipboard,chrome-clipboard,browser-chrome-clipboard
-    tier:
-        by-test-platform:
-            android-em-7.0-x86/opt: 3
-            default: default
 
 mochitest-devtools-chrome:
     description: "Mochitest devtools-chrome run"

taskcluster/ci/test/reftest.yml

@@ -55,10 +55,6 @@ crashtest:
         by-test-platform:
             android-em.*: 7200
             default: 3600
-    tier:
-        by-test-platform:
-            android-em-7.0-x86/opt: 3
-            default: default
 
 jsreftest:
     description: "JS Reftest run"