This build flag causes us to create aconfig flag artifacts for the
given extra release configs.
Bug: 298444886
Test: manual
Change-Id: I10148f6e7318b0477438ed1d8baafbf4dc594c90
Bug: 285303012
Test: for x in next trunk trunk_food trunk_staging ; do lunch aosp_panther-$x-eng ; m nothing ; done
Change-Id: I3375f46b3ecbbc516d1bee6ab3f80725fcccde8f