Any instance call with too many checks is left to be megamorphic. This helps with, e.g., LoadField …

Any instance call with too many checks is left to be megamorphic. This helps with, e.g., LoadField instructions with large number of checks and frequent deoptimization. Deoptimization improves on dart2js/swarm: total number of deoptimization 956 -> 753; number of methods becoming unoptimizable 101 -> 52.
Committed: https://code.google.com/p/dart/source/detail?r=14377

[regis, 2012-10-31 23:06:29]

LGTM