Rename Cadence CI job key from cpu (pytorch#18217)

Differential Revision: D96834252

Pull Request resolved: pytorch#18217

Author: aliafzal

.github/workflows/build-cadence-runner.yml

@@ -13,7 +13,7 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  cpu-x86:
+  cpu:
     uses: pytorch/test-infra/.github/workflows/linux_job_v2.yml@main
     permissions:
       id-token: write