Revert "Revert D25056091: migrate export_caffe2_op_to_c10.h macros to the new dispatcher registration API"
Fixing regex pattern to allow for underscores at the beginning of the
namespace
This reverts commit 3c936ecd3c68f395dad01f42935f20ed8068da02.
ghstack-source-id: 107fbdfdfc8b30679aa92608a9cc123ac1d3cd44
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48308
