Add an IS_DESTROYED flag to FullScore.

This is being added as the lowest priority score factor, just
above the tie-breakers. It ensures that a network that has been
destroyed will lose to another identical network that has not
been destroyed, but will otherwise be scored identically.

The flag is a CS-managed flag that is stored in NetworkAgentInfo.
Currently it is always false, but it will be populated in
future CLs.

Bug: 216567577
Test: atest FrameworksNetTests
Change-Id: Ib1cd342ab7dfc4df45715da19b743d711fe8d605
4 files changed