path_open ignores trailing slash when creating a file

[yagehu]

Describe the bug

This issue is an edge case of #4820. Specifically, path_open discards trailing slashes when path_open is creating a new file. This is a bug because trailing slash is semantically meaningful. Other runtimes like WasmEdge, Wazero, WAMR, Wasmtime, and Node correctly preserves the trailing slash.

Steps to reproduce

This test case can be added to tests/wasi-fyi/fs_open_trailing_slash.rs

        let errno = path_open(
            fd,
            0,
            path_bad_new_file.as_ptr() as i32,
            path_bad_new_file.len() as i32,
            OFLAGS_CREAT,
            RIGHTS_FD_READ | RIGHTS_FD_WRITE,
            0,
            0,
            1024,
        );
        assert_eq!(
            errno, ERRNO_ISDIR,
            "creating a regular file with a trailing slash should fail"
        );

Expected behavior

path_open should error with isdir.