test(dictation): skip the compat-link case where symlinks cannot be made (#993)

os.Symlink needs a privilege a Windows host may not grant; treat a
failed fixture link as unsupported rather than a test failure, matching
the pattern workspacetrust already uses.

Author: beardthelion

internal/dictation/download_test.go

@@ -3666,7 +3666,7 @@ func TestEnsureLocalEngineRefusesACompatPathThatIsASymlink(t *testing.T) {
 		t.Fatal(err)
 	}
 	if err := os.Symlink(outside, filepath.Join(root, "engine-rel", "v1-linux-amd64")); err != nil {
-		t.Fatal(err)
+		t.Skipf("os.Symlink unsupported on this platform: %v", err)
 	}
 
 	comp, err := EnsureLocalEngine(context.Background(), DownloadOptions{