To make better inlining decisions, it's good to have call counts for poly/mega-morphic cases. This CL makes it work for calls, and another will follow to better unify the code between constructor calls and normal calls (and thence, to record megamorphic call counts there as well).

BUG=

Review-Url: https://codereview.chromium.org/2325083003
Cr-Commit-Position: refs/heads/master@{#39377}