[GraphOptimizer] Reshape sinking pass

[aturetsk]

Summary:

Add Reshape sinking pass in GraphOptimizer. Currently supports only sinking below unary eltwise operators.
The sinking logic is implemented using generic node interfaces and properties (DataParallel), as opposed to having dedicated node-specific code for each operator. The benefits of this approach are:

1. Every unary elementwise operator is covered by the pass. If we ever add a new unary eltwise operator it's going to participate in Reshape sinking transformations automatically.
2. Backend-specific nodes (if they are unary and marked as DataParallel in node description) will benefit from this transformation as well, i.e. no need for backend to implement it.

Also, remove Clip sinking below Reshape, as Clip is handled by Reshape sinking pass now.

Documentation:
N/A

Fixes #5247 (partially)

Test Plan:
Added a GraphOptz unit test.

[aturetsk]

cc: @jfix71

[jfix71]

🚢

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[aturetsk]

@jfix71, thanks for review.

Would that be ok if I refactor Transpose sinking transformations for unary/binary element-wise operators in the same way (to make them use generic Node interfaces and DataParallel property) to get the same benefits I listed above? IMO having a set of generic optimizations which are enabled for a node if it has a specific property is a good thing. What's your opinion?

[jfix71]

@aturetsk Yeah, I think it's generally a good idea. We have this data parallel marker but aren't using it very well 🙂 We had issue #1830 a while back which mentions something similar.

[aturetsk]

@jfix71, can we land this?

[facebook-github-bot]

@jfix71 merged this pull request in 4139e75.