libkernel: lstat, access, chmod, truncate, utimes and readlink of a regular file named with a trailing slash fail with ENOENT or EINVAL instead of ENOTDIR (Windows) #8770

Windows host, file a regular file: lstat("file/"), access("file/", F_OK) and utimes("file/", NULL) return -1 with errno 2; chmod("file/", 0600), truncate("file/", 0) and readlink("file/", buf, n) return -1 with errno 22.
Expected (FreeBSD 11.4 lookup(), sys/kern/vfs_lookup.c:1072, a trailing slash requires the result to be a directory): ENOTDIR (20), as stat("file/") and, with #8680, unlink, remove, rename and open already answer.
Test: core/libs/tests/GuestFilesystem.cpp, core/libs/tests/GuestKernelSys.cpp (new cases).
Fix branch: https://github.com/xXPBSXx/AnyPS5/tree/fix/trailing-slash-enotdir-2
AI-assisted (Claude Code).