We benefit from the optimizing compiler even if the IC state is generic,
so we'd better ignore the generic IC state count for the optimization
decision. This improves our speedometer score from 61.5 to 63.7
(default configuration is 65.9).

Review-Url: https://codereview.chromium.org/2674203002
Cr-Commit-Position: refs/heads/master@{#42955}