[caffe2] Register BlackBoxPredictor AllocationArenaPool as CPUCachingAllocator (#48161)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48161
- Register BlackBoxPredictor AllocationArenaPool as CPUCachingAllocator
- Use the AllocationArenaPool in both BlackBoxPredictor and StaticRuntime
Test Plan:
```
buck run //caffe2/caffe2/fb/predictor:black_box_predictor_test
buck run //caffe2/caffe2/fb/predictor:pytorch_predictor_test
```
AF canary:
https://www.internalfb.com/intern/ads/canary/431021257540238874/
Reviewed By: dzhulgakov
Differential Revision: D24977611
fbshipit-source-id: 33ba596b43c1e558c3ab237a0feeae93565b2d35
