startop: Fix scripts and add --reportfullydrawn

Fixes a bug in the scripts which prevented true cold starts from
happening (it was force-stopping the activity after the dropcaches).

Also adds -rfd/--reportfullydrawn to make rfd parsing optional since
most apps don't have it.

Bug: 150237362
Test: run_app_with_prefetch -r cold
Change-Id: I132bfc3ccd4d96f171ed364ef64387bbf2c78091