Fix named tensor test

[zou3519]

Stack from ghstack:

• [WIP][testing] Turn on BUILD_NAMEDTENSOR permanently #25181 [WIP][testing] Turn on BUILD_NAMEDTENSOR permanently
• Move BUILD_NAMEDTENSOR macro out of header areas #25256 Move BUILD_NAMEDTENSOR macro out of header areas
• Fix dependency by moving Dimname.{h,cpp} NamedTensor.{h,cpp} to core/ #25280 Fix dependency by moving Dimname.{h,cpp} NamedTensor.{h,cpp} to core/
• Include the correct header for make_unique in named tensor headers #25178 Include the correct header for make_unique in named tensor headers
• Implement name inference for torch.matmul #25177 Implement name inference for torch.matmul
• Implement name inference for torch.bmm #25123 Implement name inference for torch.bmm
• Fix named tensor test #25313 Fix named tensor test

sign was recently ported from TH to ATen, undoing some named tensor
changes and breaking the CI named tensor test. This PR re-enables named tensor
for sign.

Test Plan

• [namedtensor ci]

Differential Revision: D17093439

[facebook-github-bot]

@zou3519 merged this pull request in e335cc3.