RFR(S): 8071999: SA's buildreplayjars fail with exception

[Roland Westrelin]

buildreplayjars sometimes fail with an exception and I think that's
caused by the lack of support for default methods when the SA dumps
classes. This change fixes it at least partially. It may not be the
cleanest way to support default methods but it already proved useful
when investigating a compiler crash so unless someone has a better fix
I would like to push it.

http://cr.openjdk.java.net/~roland/8071999/webrev.00/

Roland.