Code Review Request, JDK-8081792, buffer size calculation issue in NativeGCMCipher

[Xuelei Fan]

Hi Weijun or Valerie,

Can I get a quick code review for this simple fix?  DTLS implementation
exposes the bug.  There are a few new nightly testing failure.  No new
regression test. The existing test cases (the nightly testing failure)
can be used as regression test instead.

Webrev: http://cr.openjdk.java.net/~xuelei/8081792/webrev.00/

Thanks,
Xuelei