os2: skip dir test when unsupported

core/os/os2/dir_linux.odin

@@ -13,7 +13,7 @@ _read_directory_iterator :: proc(it: ^Read_Directory_Iterator) -> (fi: File_Info
 
 @(require_results)
 _read_directory_iterator_create :: proc(f: ^File) -> (Read_Directory_Iterator, Error) {
-	return {}, nil
+	return {}, .Unsupported
 }
 
 _read_directory_iterator_destroy :: proc(it: ^Read_Directory_Iterator) {

tests/core/os/os2/dir.odin

@@ -1,6 +1,7 @@
 package tests_core_os_os2
 
 import os "core:os/os2"
+import    "core:log"
 import    "core:path/filepath"
 import    "core:slice"
 import    "core:testing"
@@ -15,6 +16,11 @@ test_read_dir :: proc(t: ^testing.T) {
 
 	slice.sort_by_key(fis, proc(fi: os.File_Info) -> string { return fi.name })
 
+	if err == .Unsupported {
+		log.warn("os2 directory functionality is unsupported, skipping test")
+		return
+	}
+
 	testing.expect_value(t, err, nil)
 	testing.expect_value(t, len(fis), 2)