Switching JDK 8 over to the new build system

[mark.reinhold at oracle.com]

In preparation for switching over to the new build system [1] we
promoted build 73 this past Wednesday, one day earlier than usual.
The new build system will be made the default in a changeset to be
pushed shortly.  We'll promote build 74 as usual next Thursday.

At some point we'll also promote a build 73a, in which the only
difference from build 73 will be that it's built with the new build
system.  Experience has shown such builds to be useful to future
code archaeologists.

- Mark


[1] http://openjdk.java.net/jeps/138