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

[Alejandro Álvarez Ayllón via cfe-commits]

alejandro-alvarez-sonarsource wrote:

Thanks! I have added a new test file where the values are those of [FreeRTOS](https://www.freertos.org/Documentation/api-ref/POSIX/fcntl_8h.html)

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