Revert D24923679: Fixed einsum compatibility/performance issues (#46398)
Test Plan: revert-hammer
Differential Revision:
D24923679 (https://github.com/pytorch/pytorch/commit/ea2a568cca71aaf690051782c225ca9dd2e5e1f9)
Original commit changeset: 47e48822cd67
fbshipit-source-id: 52f17b66a4aa075d0159bdf1c98616e6098091b8
