Move lint job to new, combined CI workflow (#22386)

* Move lint job to new, combined CI workflow

Moves the lint job our new, combined CI workflow.

After this, there is only one job remaining to be migrated. Then we
can delete the old workflow and build script.

* Remove "stable" CI workflow

This workflow is now empty so we can remove it

.circleci/config.yml

@@ -343,16 +343,6 @@ jobs:
 
 workflows:
   version: 2
-  stable:
-    unless: << pipeline.parameters.prerelease_commit_sha >>
-    jobs:
-      - setup
-      - yarn_lint:
-          requires:
-            - setup
-      - RELEASE_CHANNEL_stable_yarn_build:
-          requires:
-            - setup
 
   experimental:
     unless: << pipeline.parameters.prerelease_commit_sha >>
@@ -378,6 +368,9 @@ workflows:
       - sync_reconciler_forks:
           requires:
             - setup
+      - yarn_lint:
+          requires:
+            - setup
       - yarn_test:
           requires:
             - setup