Fix duplicated Edge Runtime warnings (#48987)
When we enable `webpackBuildWorker` this module level `const apiRouteWarnings = new LRUCache({ max: 250 })` will be created in 3 workers, so users will see 4 outputs (last one is static optimization):
<img width="740" alt="CleanShot 2023-04-29 at 20 20 38@2x" src="https://user-images.githubusercontent.com/3676859/235318861-2ec12e30-70b2-4b56-8a2e-df08d130c349.png">
This PR fixes that and now there's only 1.
