Interface for swapping inputs and outputs based on cost model + working permute example

[DrJessop]

Summary:
I have seen the following pattern quite a bit so far where we have

wrapper(x0), wrapper(x1), x2 -> op -> wrapper(o0), o1

for example, and it is semantically equivalent to instead run
x0, x1, wrapper(x2) -> op -> o0, wrapper(o1)

In case 1, we had 3 wrapper ops, and in case 2, we have 2, so it's better to run 2. This interface formalizes this idea. I also implemented the pass which uses this interface for the permute case.

What is really nice about this interface is that in a single pass, we can do a LOT of cleanup. See the docs in the diff for a case for adds.

Differential Revision: D100917820

[pytorch-bot]

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❌ 2 New Failures, 1 Cancelled Job, 2 Unrelated Failures

As of commit c5916b3 with merge base 2f339f0 ():

NEW FAILURES - The following jobs have failed:

• pull / unittest / macos / macos-job (gh)
  examples/models/test/test_export.py::ExportTest::test_mv3_export_to_executorch
• pull / unittest-editable / macos / macos-job (gh)
  examples/models/test/test_export.py::ExportTest::test_mv3_export_to_executorch

CANCELLED JOB - The following job was cancelled. Please retry:

• Build Presets / zephyr (zephyr) / build (gh)

BROKEN TRUNK - The following jobs failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / unittest / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / unittest-editable / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.

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[meta-codesync]

@DrJessop has exported this pull request. If you are a Meta employee, you can view the originating Diff in D100917820.

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