Migrate benchmarks CI from ubuntu-latest to cpu-latest (#24286)

Co-authored-by: Laughing-q <1185102784@qq.com>

.github/workflows/ci.yml

@@ -51,7 +51,7 @@ jobs:
       fail-fast: false
       matrix:
         # Temporarily disable windows-latest due to https://github.com/ultralytics/ultralytics/actions/runs/13020330819/job/36319338854?pr=18921
-        os: [ubuntu-latest, macos-26, ubuntu-24.04-arm]
+        os: [cpu-latest, macos-26, ubuntu-24.04-arm]
         python: ["3.12"]
         model: [yolo26n]
     steps:
@@ -89,7 +89,7 @@ jobs:
         run: coverage run -a --source=ultralytics -m ultralytics.cfg.__init__ benchmark model='path with spaces/${{ matrix.model }}-pose.pt' imgsz=160 verbose=0.185
       - name: Benchmark OBBModel
         shell: bash
-        run: coverage run -a --source=ultralytics -m ultralytics.cfg.__init__ benchmark model='path with spaces/${{ matrix.model }}-obb.pt' imgsz=160 verbose=0.372
+        run: coverage run -a --source=ultralytics -m ultralytics.cfg.__init__ benchmark model='path with spaces/${{ matrix.model }}-obb.pt' imgsz=160 verbose=0.371
       - name: Merge Coverage Reports
         run: |
           coverage xml -o coverage-benchmarks.xml
@@ -355,7 +355,7 @@ jobs:
       - name: Benchmark PoseModel
         run: python -m ultralytics.cfg.__init__ benchmark model='yolo26n-pose.pt' imgsz=160 verbose=0.185
       - name: Benchmark OBBModel
-        run: python -m ultralytics.cfg.__init__ benchmark model='yolo26n-obb.pt' imgsz=160 verbose=0.372
+        run: python -m ultralytics.cfg.__init__ benchmark model='yolo26n-obb.pt' imgsz=160 verbose=0.371
       - name: Benchmark Summary
         run: |
           cat benchmarks.log