Rename flatbuffer_all to flatbuffers_jit (#82826)
flatbuffer_all is a bit confusing. It's actually for full jit. Rename it accordingly. For the follow up changes, will create a target for mobile only.
Differential Revision: [D38412158](https://our.internmc.facebook.com/intern/diff/D38412158/)
**NOTE FOR REVIEWERS**: This PR has internal Facebook specific changes or comments, please review them on [Phabricator](https://our.internmc.facebook.com/intern/diff/D38412158/)!
Differential Revision: [D38412158](https://our.internmc.facebook.com/intern/diff/D38412158)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/82826
Approved by: https://github.com/qihqi
