[PyTorch][Mobile] Fix the operator latency issue.
Summary: Last diff enabled operator stats for non-production build including AIBench. But the operator latency is off: https://our.intern.facebook.com/intern/aibench/details/414567479798816 as it is representing operator execution end time, and as the threadLocalDebugInfo was not set, the start time is 0. So this diff is fixing it by creating a new ThreadLocalDebugInfo object when op starts to run and store the model information for logging.
Test Plan:
```buck run mode/mac aibench:run_bench_macos -- -b aibench/specifications/models/pytorch/pytext/pytext_mobile_inference.json --platform android --framework pytorch --remote --devices SM-G960F-8.0.0-26```
https://our.intern.facebook.com/intern/aibench/details/922804117425407
```buck run mode/mac aibench:run_bench_macos -- -b aibench/specifications/models/pytorch/fbnet/fbnet_mobile_inference.json --platform android --framework pytorch --remote --devices SM-G960F-8.0.0-26```
https://our.intern.facebook.com/intern/aibench/details/593403202250750
Reviewed By: xta0
Differential Revision: D20436388
fbshipit-source-id: 740bc94c3f51daef6af9b45c1ed7a708f5fc8836
