Revert of [profiler] Update cpu profile tracing format. (patchset #2 id:20001 of https://chromiumcodereview.appspot.com/2425093002/ )

Reason for revert:
Breaks
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/10805

See also:
https://github.com/v8/v8/wiki/Blink-layout-tests

Original issue's description:
> [profiler] Update cpu profile tracing format.
>
> Encapsulate nodes and samples into cpuProfile object.
>
> BUG=chromium:406277

TBR=caseq@chromium.org,lpy@chromium.org,yangguo@chromium.org,alph@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:406277

Review-Url: https://chromiumcodereview.appspot.com/2432373004
Cr-Commit-Position: refs/heads/master@{#40452}