cargo_embargo: dedup output modules

This is needed because of https://crrev.com/c/4517945. The new resolver
causes there to be multiple `rustc` invocations for some libraries. They
are only trivially different though, so dedup'ing the final output is
sufficient for now.

Bug: 280489895
Test: m cargo_embargo && ./android-merge-2-cargo-embargo.sh
Change-Id: If4a36e4f3847d18d03f76bad63bab6c45a9aef97
2 files changed