Enable LTO in cargo2android.py.

The latest compiler roll also enabled LTO.  This broke
cargo2android.py, as the test prebuit uses LTO and so cannot be linked
with code built without.  We fix this by enabling it in
cargo2android.py (and ensuring it doesn't add the flag into
Android.bp).

Test: Run
Change-Id: I6c6a813ff58a9e5064752aa59b78247c4af77a26
1 file changed