Fix torchinductor uint8 bug (#101468)
Fixes #96604
## Issue description
When we use a constant tensor with a uint8 type, the kernel generated by torchinductor output wrong results. For example, the negative value of `5` in uint8 will be `255`, and it is `True` that `255` is larger than `5`. However, the output result is `False` when we compare `torch.neg(5)` with `5`. It is because torchinductor bypass the data type for constant tensors and the `5` here is taken as a int32. Then, the comparison is between `-5` with `5`.
## Solution
This PR generates an extra conversion for uint8 constant value when we use it. it does not occur on the first assignment but the access for this constant value.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/101468
Approved by: https://github.com/desertfire, https://github.com/jansel
