[fuchsia] Add Fuchsia support to SQLite.

This enables basic database locking, but there are known weaknesses to this
approach. ie. If the process is killed before the *.lock file can be
deleted, then the database is perpetually locked.

Bug: 120103808
Test: Database locking works.
Change-Id: Iac54c5f76e167fef15b490522840d33808d4bc6c