Implement array bounds checks explicitly in the optimized IL.

Implement array bounds checks explicitly in the optimized IL.

They are inserted by the flow-graph optimizer when specializing
array operations.

As a result, LoadIndexed and StoreIndexed can't deoptimize themselves
anymore. All checks happen before in check-instructions.

Redundant array bound checks can be eliminated by CSE if all operands
match.
Committed: https://code.google.com/p/dart/source/detail?r=11433

[srdjan, 2012-08-27 16:53:52]

lgtm