ART: Make test 030 slightly more robust

Run a serious of immediate GCs, synchronizer with the finalizer
starintg  and then let the main thread sleep for a minute, in an
effort to make the test deterministic and get the finalizer
daemon scheduled.

Test: m test-art-host-run-test-030-bad-finalizer
Change-Id: Id379d8147ecc8f6aa0a7d8d5058030a4c2d4de46