This patch adds runtime call stats tracing for GC correctly, makes
--runtime-call-stats and tracing mutually exclusive with tracing taking
precedence if both modes are on, and uses only one runtime call stats in
counter.

BUG=v8:5089

Review-Url: https://codereview.chromium.org/2313193002
Cr-Commit-Position: refs/heads/master@{#39295}