Add the new buildbotless infra-tests bot to the CQ as an experiment

infra/branch-config/cq.cfg

 # Commit Queue configuration file. The documentation of the format can be found
 # at http://luci-config.appspot.com/schemas/projects/refs:cq.cfg.
 
 version: 1
 cq_name: "skia"
 cq_status_url: "https://chromium-cq-status.appspot.com"
 git_repo_url: "https://skia.googlesource.com/skia/"
 gerrit {}
 
 commit_burst_delay: 300
@@ skipping 40 matching lines @@
     }
     buckets {
       name: "master.client.skia.android"
       builders { name: "Test-Android-Clang-Nexus5-GPU-Adreno330-arm-Release-GN_Android-Trybot" }
     }
     buckets {
       name: "master.tryserver.chromium.mac"
       # At time of writing, this is the fastest Chrome compile bot on average.
       builders { name: "mac_chromium_compile_dbg_ng" }
     }
+    buckets {
+      name: "skia.primary"
+      builders {
+        name: "Housekeeper-PerCommit-InfraTests"
+        experiment_percentage: 100
+      }
+    }
     try_job_retry_config {
       try_job_retry_quota: 1
       global_retry_quota: 2
       failure_retry_weight: 2
       transient_failure_retry_weight: 1
       timeout_retry_weight: 2
     }
   }
 
   sign_cla {}
 }