make duplicate def() calls an error in the dispatcher (#48098)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/48098
Test Plan:
Imported from OSS
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make duplicate def() calls an error in the dispatcher. Updating all fb operators to use the new dispatcher registration API
Reviewed By: ezyang
Differential Revision: D25056089
Pulled By: bdhirsh
fbshipit-source-id: 8d7e381f16498a69cd20e6955d69acdc9a1d2791
