Add verify_vintf_matrices.

Modules declare 'vintf_fragments' much like
they declare 'rc_file'. These are verified
in mass during a device build.

Test: `m` can cause verify_vintf_matrices to
    pass or fail.
Test: build OTA package and check to make sure it
    contains the correct assembled matrices.
Bug: 66917623

Change-Id: I504985100069456a0ca4d0180387d271bb283d49