[PyTorch] Revert tensor dimensions in MXFP8 tests

[timmoon10]

Description

We increased the tensor dimensions in some unit tests due to an MXFP8 requirement that tensor dims are multiples of 128, but this also increased numerical errors and caused test failures. #1431 relaxed that constraint to being a multiple of 32, so this PR reverts the unit test tensor dimensions back to their original values.

Type of change

• Documentation change (change only to the documentation, either a fix or a new content)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Infra/Build change
• Code refactoring
• Testing

Changes

• Revert tensor dimensions in MXFP8 tests

Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[timmoon10]

Pipeline 23264050