[clang] [analyzer] Canonicalize the Decls of FieldRegions (PR #156668)

[Donát Nagy via cfe-commits]

https://github.com/NagyDonat approved this pull request.

The patch LGTM, it is always good to see a fix for a crash.

I added two very minor stylistic suggestions in inline comments, but I think the change is acceptable even without those changes.

https://github.com/llvm/llvm-project/pull/156668