fix: change floordiv to divmod for //tests/core/lowering:test_remove_unnecessary_casts

[zewenli98]

Description

An error was reported on NVBug:

[  FAILED  ] 2 tests, listed below:
[  FAILED  ] LoweringPasses.RemoveSingleUse0DTensorsFloorDivIntCorrectly
[  FAILED  ] LoweringPasses.RemoveSingleUse0DTensorsFloorDivFloatCorrectly

With log:
unknown file: Failure
C++ exception with description "
Schema not found for node. File a bug report.
Node: %7 : int = aten::floor_divide(%6, %0)

Input types:int, int
candidates were:
  aten::floor_divide(Tensor self, Tensor other) -> Tensor
  aten::floor_divide.Scalar(Tensor self, Scalar other) -> Tensor
  aten::floor_divide.out(Tensor self, Tensor other, *, Tensor(a!) out) -> Tensor(a!)
  aten::floor_divide.Scalar_out(Tensor self, Scalar other, *, Tensor(a!) out) -> Tensor(a!)
within the graph:
graph(%0 : int):
  %6 : int = prim::Constant[value=7]()
  %7 : int = aten::floor_divide(%6, %0)
  %4 : int = aten::Int(%7)
  return (%4)

:
" thrown in the test body.

The error is because Pytorch changed the schema of aten::floor_divide. Previously it supported two ints/floats as inputs, but the new schema requires the first input to be Tensor, while the lowering pass RemoveSingleUse0DTensors lowers two inputs to int/float.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project (You can use the linters)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas and hacks
• I have made corresponding changes to the documentation
• I have added tests to verify my fix or my feature
• New and existing unit tests pass locally with my changes
• I have added the relevant labels to my PR in so that relevant reviewers are notified

[narendasan]

Do these C++ tests pass? Doesnt divmod return two outputs?

[narendasan]

LGTM