Disable NVFuser in internal (Meta) build (#91836)
In preparation for https://github.com/pytorch/pytorch/pull/89621.
The build changes in #89621 would require re-writing the internal build
in order to get NVFuser support. As-is, #89621 would disable NVFuser in
the internal build; so I would need to add some internal-only changes
associated with the internal copy of the PR (not visible from github) to
fix the internal build.
However, I don't think NVFuser is actually being used internally
anywhere at the moment, so it may be easier to land #89621 as is, and
then we can fix the internal build later if needed. To verify that, I
want to land this PR instead to flush out any issues caused by disabling
NVFuser. If the PR lands without issues, then we can move on to landing #89621.
If the PR breaks things internally, then it will need to be reverted;
and that will probably be easier than having to revert and reland #89621.
Differential Revision: [D42398050](https://our.internmc.facebook.com/intern/diff/D42398050)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/91836
Approved by: https://github.com/jjsjann123
