[quant][core][gpu][feature] Added support for float->quantized cuda tensor copying (#76177)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76177
Previously, support for copying a fp tensor to a quantized tensor was
limited to CPU tensors. This PR extends the support to GPU tensors.
A corresponding test was added to test_qtensor_float_assignment for cuda
tensors
Test Plan:
```
python test/test_quantization.py -k test_qtensor_float_assignment
```
Imported from OSS
Differential Revision:
D35817832
D35817832
Reviewed By: jerryzh168
Pulled By: dzdang
fbshipit-source-id: e5a4a0bb2d8a56f3f1a88806a534b5cb38275cf2
(cherry picked from commit 9173e07b51bb1b853244b205ddf3e36000f01b64)
