Match Ycbcr TIFF decoding to rasterio/libtiff

Currently we have two python tests that don't have exactly the same decoded values as rasterio/libtiff.

https://github.com/developmentseed/async-tiff/blob/402c0a5e15fa42d84af06f1731d816ae535e1d45/python/tests/test_integration_rasterio.py#L44-L48

```
E AssertionError:
E Arrays are not equal
E
E Mismatched elements: 7858 / 49152 (16%)
E Max absolute difference among violations: 4
E Max relative difference among violations: 0.33333333
E ACTUAL: array([[[141, 146, 139],
E [141, 146, 139],
E [160, 163, 154],...
E DESIRED: array([[[141, 146, 139],
E [141, 146, 139],
E [160, 163, 154],...

E AssertionError:
E Arrays are not equal
E
E Mismatched elements: 212 / 12288 (1.73%)
E Max absolute difference among violations: 3
E Max relative difference among violations: 0.0483871
E ACTUAL: array([[[54, 75, 56],
E [59, 80, 61],
E [64, 85, 66],...
E DESIRED: array([[[54, 75, 56],
E [59, 80, 61],
E [64, 85, 66],...
```

Start with python/tests/test_integration_rasterio.py at the linked assertions and reproduce the two mismatches. Trace the YCbCr TIFF decoding path, compare its output with rasterio/libtiff, and update the implementation and tests until both decoded arrays match.

Written by the indexing model from the issue text.