RFR: JDK-8030794: Update configure to require jdk8 as boot

[Chris Hegarty]

Thanks Erik, looks good to me.

-Chris.

On 19 Dec 2013, at 13:32, Erik Joelsson <erik.joelsson at oracle.com> wrote:

> Since we now have dependencies in the langtools source on jdk8 features, we can no longer build jdk9 with jdk7 as boot. This change updates configure to allow jdk8 and jdk9 as boot jdks.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8030794
> Webrev: http://cr.openjdk.java.net/~erikj/8030794/webrev.root.01/
> 
> /Erik