fix celu in quantized benchmark (#42756)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/42756
Similar to ELU, CELU was also broken in the quantized benchmark, fixing.
Test Plan:
```
cd benchmarks/operator_benchmark
python -m pt.qactivation_test
```
Imported from OSS
Reviewed By: jerryzh168
Differential Revision: D23010863
fbshipit-source-id: 203e63f9cff760af6809f6f345b0d222dc1e9e1b
