Fix delegate for constants, parameters, buffers

Summary:
Fix constant tensors for delegate.

Since exported program added constant tensors, we need to update our logic for finding and getting constants, buffers, parameters

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Reviewed By: cccclai, kirklandsign

Differential Revision: D54149275

fbshipit-source-id: 3a13939fe35e235056fc20e35c29716ef064735b