Make everything buildable in prep for release.

Note that this only builds from the existing XML file, and there
is no logic yet to build the XML file itself (via XMLGen). Because
the XML only needs to be rarely generated and already includes
the jsr292 changes up through Java 8, we can install this step
later. You can also just run XMLGen directly to update the XML
file manually, and then commit the result.
[maven-release-plugin] prepare release jsr292-mock-1.0