[clang] [analyzer] UnixAPIMisuseChecker Get O_CREAT from preprocessor (PR #81855)

[Balázs Kéri via cfe-commits]

https://github.com/balazske commented:

Code change looks good, but I could not verify the new test. Probably it is not tested if it works with a non-usual O_CREAT value (that is parsed by the checker).

https://github.com/llvm/llvm-project/pull/81855