init: handle properties and imports for host init verifier

Allow specifying properties on the command line when running host init
verifier.  This is needed particularly for importing files that have a
property expansion in their path.

Handle the import statement on host, basing paths off of the out
directory of Android builds.

Bug: 36970783
Test: verify that bullhead imports the correct files and checks them
Change-Id: I4fe263016b3764a372708b559bc0c739b1b7e5e3