This shortens the gap between A/B and non-A/B builds, by replacing the
dependency on build-time flag with runtime detection instead. It also
allows building and testing both paths regardless of the target OTA
type.
The size increase to /sbin/recovery looks negligible (< 0.01%).
- marlin: increased from 2084928 to 2085024;
- angler: increased from 2084776 to 2084896.
Test: Run recovery_component_test on angler and marlin.
Test: Sideload an A/B OTA package on marlin.
Test: Sideload a non-A/B OTA package on angler.
Change-Id: I1d927d1ede9713fb42f73b4fe324aa5705ee6f99
cf60a44bd4