Revert "Remove exception from OverlayConfig zygote method"

Commit ag/9740370 caused problem with robotests b/149806146
The fix ag/10373855 froze targets like run_host_tests
This revert will unfreeze run_host_tests but robotests will break

Bug: 150011638
Test: m RunSettingsRoboTests0
Change-Id: Ibe954e9d0dc1542477ba7156da5799479631cfb0