HalManifests can be merged.

assemble_vintf and VintfObject can now merge manifests
correctly (previously, only <hal>'s are merged).

Test: libvintf_test
Test: vintf_object_test
Fixes: 78943004
Change-Id: I5e2987e9c97e0b60e976fe4e0bb8833edf043a53
10 files changed