Selectively allow dead reference elimination

Allow dead reference elimination in methods not containing
@ReachabilitySensitive accesses or calls, when the class is marked
@DeadReferenceSafe.

Add 1339-dead-reference-safe to aggressively check that everything
works as intended.

Bug: 111453875

Test: art/test/testrunner/testrunner.py --host --64 -t 1339-dead-reference-safe

Detect ReachabilitySensitive annotations.

Change-Id: I70c20431fdbcfcfd2692b2255d12ad59e37cb669