[clang] [clang][analyzer] fix false positive of BlockInCriticalSectionChecker (PR #126752)

[via cfe-commits]

flovent wrote:

I thought about the case when file descriptor equals to -1, which is modeled by `evalcall` for `open` in testcase, means that `open` failed to get a valid file descriptor, if we use this file descriptor in `read` or `recv`, they will not be blocked since no actual read is performed, this will not take a long time like this checker's description concerns, so maybe we should avoid report for this situation like non-block file descriptor as well?

https://github.com/llvm/llvm-project/pull/126752