Load default/build props from each partition

The following files will be loaded additionally.
- /odm/default.prop and /vendor/default.prop for default props.
- /odm/build.prop for build props.

The props files must follow the following priority order.
- /default.prop > /odm/default.prop > /vendor/default.prop
- /system/build.prop > /odm/build.prop > /vendor/buid.prop

Test: tested default/build prop files with enabling early mount, but
didn't test files of odm partition because odm partition doesn't
exist now.
Bug: 34116668
Change-Id: I946d076dae38f2288865dd986fb16d801d4abcc0