RFR [14] 8226303: Examine the HttpRequest.BodyPublishers for exception handling

[Pavel Rappo]

Hello,

Please review the following change:

 http://cr.openjdk.java.net/~prappo/8226303/webrev.00

This change increases robustness of convenience BodyPublishers by going the
extra mile and ensuring unlikely thrown exceptions are relayed downstream.

Thanks,
-Pavel