This turns on collection of function size bytes, and decode time for functions in all cases (both background and foreground).

Bug: v8:6361
Change-Id: I5d982ec4452596210b3ea9858126820ad0c3eacf
Reviewed-on: https://chromium-review.googlesource.com/568781
Commit-Queue: Karl Schimpf <kschimpf@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46605}