Add Helium 7 support for package builds.
- During operation, if last.major.helium.version is detected as 7.0 then it will use new sbsinput mechanism.
- Restore sf-postbuild dependency on sf-build-noprep target
<?xml version="1.0"?>
<project name="SF-PACKAGE-REFS">
<path id="sf.spec.system.definition.files">
<fileset dir="${sf.spec.job.drive}/" casesensitive="false">
<include name="${sf.spec.systemdefinition.location}"/>
</fileset>
</path>
</project>