Create experimental FX graph manipulation library (#44775)
Summary:
This PR adds a new GraphManipulation library for operating on the GraphModule nodes.
It also adds an implementation of replace_target_nodes_with, which replaces all nodes in the GraphModule or a specific op/target with a new specified op/target. An example use of this function would be replacing a generic operator with an optimized operator for specific sizes and shapes.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44775
Reviewed By: jamesr66a
Differential Revision: D23874561
Pulled By: gcatron
fbshipit-source-id: e1497cd11e0bbbf1fabdf137d65c746248998e0b
