[dte] scaffolding for c2 operator broadcasting fastpath (1/x) (#62369)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62369
This diff is a big no-op that just sets up scaffolding for passing the "allow_broadcast_fastpath" from caffe2 operator protos created in Python down to C++. To facilitate this, we create helper template wrappers that pass a flag for "allow_broadcast_fastpath" down to elementwise functors. This flag will determine whether to try and take the broadcast fastpath, which we will add in subsequent diffs.
Test Plan: sandcastle + let github CI run
Differential Revision: D28154475
fbshipit-source-id: 15750a0bcd2994fbc6a61fb5653d8cae6b0177dd
