Add option to warn if elements in a Compare table are suspect (#41011)
Summary:
This PR adds a `.highlight_warnings()` method to `Compare`, which will include a `(! XX%)` next to measurements with high variance to highlight that fact. For example:
```
[------------- Record function overhead ------------]
| lstm_jit | resnet50_jit
1 threads: ------------------------------------------
with_rec_fn | 650 | 8600
without_rec_fn | 660 | 8000
2 threads: ------------------------------------------
with_rec_fn | 360 | 4200
without_rec_fn | 350 | 4000
4 threads: ------------------------------------------
with_rec_fn | 250 | 2100
without_rec_fn | 260 | 2000
8 threads: ------------------------------------------
with_rec_fn | 200 (! 6%) | 1200
without_rec_fn | 210 (! 6%) | 1100
16 threads: -----------------------------------------
with_rec_fn | 220 (! 8%) | 900 (! 5%)
without_rec_fn | 200 (! 5%) | 1000 (! 7%)
32 threads: -----------------------------------------
with_rec_fn | 1000 (! 7%) | 920
without_rec_fn | 1000 (! 6%) | 900 (! 6%)
Times are in milliseconds (ms).
(! XX%) Measurement has high variance, where XX is the median / IQR * 100.
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/41011
Differential Revision: D22412905
Pulled By: robieta
fbshipit-source-id: 2c90e719d9a5a1c0267ed113dd1b1b1738fa8269
