Use getProjection instead of getUnpacked in getIxImpl
Use getProjection instead of getUnpacked in getIxImpl

We know that synthesis always returns atoms that should be ready to
unpack, so there's no need to cheapReduce them.

google-research/dex-lang,google-research/dex-lang,google-research/dex-lang,google-research/dex-lang,google-research/dex-lang,google-research/dex-lang