quantized_tensor tests (#25429)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25429
Previously we are using empty to generate test tensors, this PR changes the test tensors to use
randint so that we can test things properly
Also added a set_sizes_and_strides and removed .contiguous() in int_repr function to preserve the
original size and strides
Test Plan:
python test/test_quantized_tensor.py
Imported from OSS
Differential Revision: D17559660
fbshipit-source-id: d4ce81d577296c1137270fdaa6b1359fb703896f
