Revert "scripts: Add support for reboots that don't factory reset"

Revert submission 3120532-trusty-qemu-reboot

Reason for revert: Rebuilding AOSP system.img has no effect if the images are already copied and exist. That breaks running run.py independently without tests. This isn't the way to do this, and we shouldn't be snapshotting system and vendor anyway.

Reverted changes: /q/submissionid:3120532-trusty-qemu-reboot

Change-Id: Ic4688ac18fc55eac0f7690b342d20d441d75e4ec
2 files changed