[test] Skip named_pipe_script_test in reload stress testing.

It's not possible to re-read source from a pipe.

Bug: #36254
Change-Id: I22cafd5ce0eaadc7d3d172219cb5cb8bbed27f91
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/409201
Reviewed-by: Alexander Aprelev <[email protected]>
Commit-Queue: Ryan Macnak <[email protected]>

Author: rmacnak-google

tests/standalone/standalone_vm.status

@@ -72,3 +72,6 @@ io/named_pipe_script_test: Skip # Issue 28737
 io/dart_std_io_pipe_test: Timeout, Pass
 io/http_client_stays_alive_test: Skip # Spawns process in Dart2 mode.
 io/process_sync_test: Timeout, Pass
+
+[ $hot_reload || $hot_reload_rollback ]
+io/named_pipe_script_test: Skip # Can't read from the pipe twice