[Profiler][Trivial] Small style and safety fixes (#86752)
I noticed a couple abbreviations in the new optimizer capture code that are worth expanding. I also made the RawTensorMetadata a bit safer.
Differential Revision: [D40210702](https://our.internmc.facebook.com/intern/diff/D40210702/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/86752
Approved by: https://github.com/slgong-fb, https://github.com/aaronenyeshi
