Update kernels for non-fatal (part 6) (#2123)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/2123

Update kernels and tests starting with 'f'.

Note to reviewers: Because the changeset for non-fatal touches so many files, I've split into a number of diffs. The tests will not all pass until the final diff, given that non-fatal tests are switched on in the first diff but tests are not updated until the respective later diff. See revision 6.6 of D53251417 to observe the full change-set passing CI.

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Reviewed By: kirklandsign

Differential Revision: D54182047

fbshipit-source-id: e27eb312a88b58dc73809785fcde3b4ab54de375