This patch introduces:

1. ICStats class to store ic statistics items produced by V8,
2. A disabled by default tracing category v8.ic_stats,
3. An trace event V8.ICStats that contains ic statistics items in args,

We store ic statistics items in an array until the array is full to reduce
the number of trace events.

TBR=jkummerow@chromium.org,ishell@chromium.org

Review-Url: https://codereview.chromium.org/2503183002
Cr-Commit-Position: refs/heads/master@{#41559}