8308545: java/net/httpclient/ShutdownNow.java fails with "stream 1 cancelled"

Reviewed-by: jpai

Author: dfuch

test/jdk/java/net/httpclient/ShutdownNow.java

@@ -134,6 +134,8 @@ static boolean hasExpectedMessage(IOException io) {
         if (message.equals("closed")) return true;
         // exception from selmgr.abort
         if (message.equals("shutdownNow")) return true;
+        // exception from cancelling an HTTP/2 stream
+        if (message.matches("stream [0-9]+ cancelled")) return true;
         return false;
     }