After we landed the tracing runtime call stats, which gave
us a lot of V8 insight in tracing, we noticed that there is
some arising issues and discrepancies.

Issues include:
Missing trace events, that happened due to
transforming those trace events into runtime calls

Discrepancies include:
Missing categories in Runtime call stats like GC,
because we are not handling the Scoped runtime calls
properly in the tracing version.

To reduce/eliminate those issue, we are taking a small
step back. We are unifying the RuntimeStats code and
using the original one. That would allow us to use all
the original probes but emit trace events from them.
We are also putting back the trace-events in their place.

The output from both system should be intact (Except of
the addition of the missing trace-events).

Also as a byproduct, we are reducing the number of context
scopes by half since we are using the same scope as
runtime call stats.

As a follow up to this CL, we will address the non-scoped
Runtime Call Stats (mainly in GC).
BUG=642373

Review-Url: https://codereview.chromium.org/2296243002
Cr-Commit-Position: refs/heads/master@{#39180}