Fix wrong DCHECK in bounds check elimination.

The lower range of an array length instruction can
be changed by other instructions than HBoundsCheck,
like HNewArray.

bug:21862741

(cherry picked from commit 8d82a0c2b2b12f259ccb357d3b1e699c68ad0400)

Change-Id: I1bb1a4f4c6673509dd3fb5184c32992bed876250
4 files changed