[compiler-rt] [Sanitizers] Remove freebsd/netbsd from "posix" file (PR #123269)

[Thurston Dang via llvm-commits]

thurstond wrote:

compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.h has:
```
#if SANITIZER_FREEBSD

#  include "sanitizer_internal_defs.h"
#  include "sanitizer_platform.h"
#  include "sanitizer_platform_limits_posix.h"
```

so it's not clear whether the `#SANITIZER_FREEBSD` cases in sanitizer_platform_limits_posix.h are no-ops.

It's possible they are redundant, but it'd be useful to have strong confirmation, such as running the regression tests on FreeBSD and NetBSD.



https://github.com/llvm/llvm-project/pull/123269