Updated START_SESSION message interpretation

Removed the dependency on the fact that the core's new ID is always >= existing ID.
New ID and the old ID may not have any such relation.

Bug: 135475397
Fixes: 135475397
Test: Updated unit tests in VmsUtilsTest. Ran the tests on Hawk.

Change-Id: I5a7e72f36a84f5bf2d3c7bf1ccb89d27c5c0da97
3 files changed