Fix Unix tests

Author: deeprobin

src/libraries/System.IO.FileSystem/tests/File/GetSetAttributes_SafeFileHandle.cs

@@ -8,7 +8,7 @@ public sealed class GetSetAttributes_SafeFileHandle : FileGetSetAttributes
         protected override FileAttributes GetAttributes(string path)
         {
             using var fileHandle =
-                File.OpenHandle(path, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
+                File.OpenHandle(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
             return File.GetAttributes(fileHandle);
         }