uniform_: improve error handling and error messages.

[ysiraichi]

This PR refactors the uniform_ operation implementation by improving its error message, and returning a status type value.

Key Changes:

• Make tensor_methods::uniform_ return Status
• Improve error messages and error handling
  • Add CheckUniformRangeIsValid function

Example

a = torch.empty( 2, 2, device="xla")
a.uniform_(5, 2)

Before:

Traceback (most recent call last):
  File "examples/uniform.py", line 6, in <module>
    a.uniform_(5, 2)
RuntimeError: Check failed: from <= to (5 vs. 2) (at torch_xla/csrc/tensor_methods.cpp:3673)

Exception raised from operator& at torch_xla/csrc/runtime/tf_logging.cpp:26 (most recent call first):

After:

Traceback (most recent call last):
  File "examples/uniform.py", line 6, in <module>
    a.uniform_(5, 2)
RuntimeError: uniform_(): expected `from` (5) to be smaller or equal `to` (2).

Status Propagation Trace:
    From: CheckUniformRangeIsValid at torch_xla/csrc/tensor_methods.cpp:3659 (error: uniform_(): expected argument `from` (5) to be smaller or equal argument `to` (2).)
    From: uniform_ at torch_xla/csrc/tensor_methods.cpp:3667
    From: uniform_ at torch_xla/csrc/aten_xla_type.cpp:3910

Exception raised from ThrowStatusError at torch_xla/csrc/status.cpp:128 (most recent call first):