Bug 1432872 - Stop running test-verify on beta and release; r=ryanvm

test-verify failures on merges are low-value: They usually just repeat/confirm
the test results from the origin branch.

taskcluster/ci/test/misc.yml

@@ -70,7 +70,8 @@ test-verify:
         by-test-platform:
             # do not run on ccov; see also the enable_code_coverage transform
             linux64-ccov/.*: []
-            default: built-projects
+            # do not run on beta or release: usually just confirms earlier results
+            default: ['trunk', 'try']
     tier:
         by-test-platform:
             windows10-64-asan.*: 3

taskcluster/ci/test/web-platform.yml

@@ -137,7 +137,8 @@ test-verify-wpt:
         by-test-platform:
             # do not run on ccov; see also the enable_code_coverage transform
             linux64-ccov/.*: []
-            default: built-projects
+            # do not run on beta or release: usually just confirms earlier results
+            default: ['trunk', 'try']
     tier:
         by-test-platform:
             windows10-64-asan.*: 3