tests/ln: skip WASI-incompatible cases

- test_symlink_to_dir_2args uses an absolute host tmpdir path that
  isn't visible inside the WASI sandbox.
- test_ln_non_utf8_paths requires non-UTF-8 filenames, which WASI
  forbids.
- test_relative_src_already_symlink hits a read_link-on-absolute-path
  failure specific to wasmtime launched through cargo test's spawn.

Author: DePasqualeOrg

tests/by-util/test_ln.rs

@@ -501,6 +501,7 @@ fn test_symlink_implicit_target_dir() {
 }
 
 #[test]
+#[cfg_attr(wasi_runner, ignore = "WASI sandbox: host paths not visible")]
 fn test_symlink_to_dir_2args() {
     let (at, mut ucmd) = at_and_ucmd!();
     let filename = "test_symlink_to_dir_2args_file";
@@ -754,6 +755,10 @@ fn test_relative_dst_already_symlink() {
 }
 
 #[test]
+#[cfg_attr(
+    wasi_runner,
+    ignore = "WASI: read_link on absolute paths fails under wasmtime via spawned test harness"
+)]
 fn test_relative_src_already_symlink() {
     let (at, mut ucmd) = at_and_ucmd!();
     at.touch("file1");
@@ -967,6 +972,7 @@ fn test_ln_seen_file() {
 
 #[test]
 #[cfg(target_os = "linux")]
+#[cfg_attr(wasi_runner, ignore = "WASI: argv/filenames must be valid UTF-8")]
 fn test_ln_non_utf8_paths() {
     use std::ffi::OsStr;
     use std::os::unix::ffi::OsStrExt;