[test] Refactoring - Make perf suite definitions stateless regarding measurements.

This prepares for making multiple measurements of one trace.
For this, the suite/trace configurations need to be
independent of the measurement instances.

BUG=chromium:507213
LOG=n
NOTRY=true

Review URL: https://codereview.chromium.org/1227033002

Cr-Commit-Position: refs/heads/master@{#29531}