fx quant: fix test_fx_acc_tracer::test_quantized_batch_norm2d (#71175)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/71175
D33330022 was landed with a Meta test failure (ghstack clobbered the fix),
resubmitting the Meta-only part to fix CI.
Test Plan:
```
buck test mode/opt //caffe2/test:test_fx_acc_tracer -- --exact 'caffe2/test:test_fx_acc_tracer - test_quantized_batch_norm2d (fx_acc.test_acc_tracer.AccTracerTest)' --run-disabled
```
Reviewed By: HDCharles
Differential Revision: D33531994
fbshipit-source-id: 39dc945c54fb9a7205c9d4114ede6b5ab99c5012
