[clang] [NFC][analyzer] OOB test consolidation III: 'outofbound' tests (PR #128508)

[Donát Nagy via cfe-commits]

https://github.com/NagyDonat commented:

I annotated `outofbound.c` with inline comments to describe why I removed most of the testcases within it.

https://github.com/llvm/llvm-project/pull/128508