Add the pt2 runner and collect triton kernels
Summary: Add pt2 runner to torchbench and write about how to find generated Triton kernels from PT2.
Reviewed By: blaine-rister
Differential Revision: D57874376
fbshipit-source-id: a3aaef17b0c3f65aef1b1b07a35e5703771bc9e1
