8252374: Add a new factory method to concatenate a sequence of BodyPublisher instances into a single publisher.

[Daniel Fuchs]

Hi,

Please find below a fix for:
8252374: Add a new factory method to concatenate a sequence
         of BodyPublisher instances into a single publisher.
https://bugs.openjdk.java.net/browse/JDK-8252374


Draft CSR:
https://bugs.openjdk.java.net/browse/JDK-8252382

webrev:
http://cr.openjdk.java.net/~dfuchs/webrev_8252374/webrev.00/

best regards,

-- daniel