Ensure that make doesn't flatten zipapex files.

Zip apex files are not really installed so should not ever be
flattened. Unfortunately we didn't send this information to make which
would still unzip everything.

Test: ALLOW_MISSING_DEPENDENCIES=true
      ./art/tools/build_linux_bionic_tests.sh com.android.runtime.host
Bug: 124333446

Change-Id: I3eda579f8c40f768f1ef2be867967f436396cd4c