Remove deprecated NodeData class.

R=titzer@chromium.org

Review URL: https://codereview.chromium.org/768853002

Cr-Commit-Position: refs/heads/master@{#25575}
Abstract platform in perf runner.

This is basically a refactoring that extracts desktop
specific code into a separate class.

Also adds flags for android runs (not used yet).

BUG=chromium:374740
LOG=n
TEST=python -m unittest run_perf_test
NOTRY=true

Review URL: https://codereview.chromium.org/762163002

Cr-Commit-Position: refs/heads/master@{#25576}
Introduce a kill-switch for shipping features.

R=rossberg@chromium.org
TBR=hpayer@chromium.org

Committed: https://chromium.googlesource.com/v8/v8/+/d6285620868b15c84eb9affa59f6b4e869f074b8

Review URL: https://codereview.chromium.org/763273002

Cr-Commit-Position: refs/heads/master@{#25577}