se_build_files is a replacement for se_filegroup module. se_build_files
can be used with the normal Soong convention ":module_name{.tag}" by
implementing android.OutputFileProducer. It's better than implementing
ad-hoc logics across various modules, which is the case for se_filegroup
module.
Test: build and boot
Change-Id: Ic0e34549601eb043145e433055f5a030eaf4347e