Add ImsCall constructor tests.

In the past a null profile could cause an exception on construction.
These tests verify that a null profile won't cause a crash and that if
the profile is present, the video state tracking takes places as expected.

Test: These are tests.
Fixes: 156188660
Change-Id: Ib1fbe8caf97381f3bd7235596307c5a2c3559b8f