Check if Test Harness Mode is enabling on boot

There's currently a bug where the Test Harness Mode service will
*always* disable auto sync for accounts on boot. This CL adds a variable
that will tell its methods that have to be performed after boot is
completed whether or not they should set anything up.

Test: make && fastboot flashall -w, check if Auto Sync is enabled
Bug: 80137798
Change-Id: I73f853cbcccd259f278dcbf81f39a8c120f12972