Fix dtype mismatch in `TestParamPartitioningSkipInit` (#7377)
`TestParamPartitioningSkipInit` throws the following error.
```
====================================== short test summary info ======================================
FAILED test_zero.py::TestParamPartitioningSkipInit::test[dtype1] - RuntimeError: mat1 and mat2 must have the same dtype, but got Half and BFloat16
========= 1 failed, 204 passed, 66 skipped, 15 deselected, 5 warnings in 2305.03s (0:38:25) =========
```
The test always sets the model's dtype to `torch.bfloat16` and ignores
the test parameter `dtype` when bfloat16 is supported. This causes a
dtype mismatch when `dtype=torch.float16` is given as the test parameter
because the data loader respects the test parameter dtype.
---------
Signed-off-by: Masahiro Tanaka <mtanaka@microsoft.com>
Co-authored-by: Logan Adams <114770087+loadams@users.noreply.github.com>
