cargo2android: fix test detection when there is exactly 1 test

Example where it failed:

    tests::sock_send_recv_event: test

    1 test, 0 benchmarks
       Doc-tests vm_control
    0 tests, 0 benchmarks

the "1 test, 0 benchmarks" line wouldn't match the test regex, so it
would mistakenly parse the doc tests line instead and then fail to
generate a rust_test module.

Test: ran on crosvm repo

Change-Id: Id0286165405b58bf84b7261db842e272442c91e8
1 file changed