WasmFS test failures

A handful of tests are failing in `wasmfs` test runner mode, that look like actual issues:

`wasmfs.test_module_stdin`
- Error: EAGAIN: resource temporarily unavailable

`wasmfs.test_statvfs`
- st.f_ffree > st.f_files, same issue than in wasmfs.test_fs_nodefs_statvfs

`wasmfs.test_fs_nodefs_statvfs`
- Assertion failed: st.f_ffree <= st.f_files && "Free inodes should not exceed total inodes"

`wasmfs.test_fs_enotdir`
- Assertion failed: open("./does-not-exist/", O_CREAT, 0777) == -1 in test_fs_enotdir.c line 20

`wasmfs.test_fs_readdir_ino_matches_stat_ino`
- Assertion failed: "a_ino == sta.st" in test_fs_readdir_ino_matches_stat_ino.c, line 58

`wasmfs.test_unistd_write_broken_link`
- Assertion failed: "r == 3" in test_unistd_write_broken_link.c line 22

`wasmfs.test_unistd_symlink_on_nodefs`
- Assertion failed: "fd" in symlink_on_nodefs.c line 62

`wasmfs.test_unistd_misc`
- fails in testing fdatasync, tcgetpgrp and pipe

Apart from these remaining failures, the `wasmfs` suite seems to be in passing condition.

首先运行 wasmfs 测试运行器并重现列出的失败，尤其是 wasmfs.test_module_stdin、wasmfs.test_statvfs 和 wasmfs.test_unistd_misc。检查所引用的测试 test_fs_enotdir.c、test_fs_readdir_ino_matches_stat_ino.c、test_unistd_write_broken_link.c 和 symlink_on_nodefs.c。剩余的 wasmfs 测试在没有回归的情况下通过，即表示完成。

由索引模型根据 Issue 内容生成。