ART: Fix loop information after dead code elimination

Compilation failed when only some blocks of a loop were removed during
dead code elimination.

Bug: 20680703
(cherry picked from commit 69a2804c3bb48cf4fd00a66080f613a4fd96c422)

Change-Id: If9988381236e4d8d8c3b508dfce1376b27c20d75
4 files changed