Keystore 2.0: Move per-boot database out of SQLite

Being in SQLite incurs a variety of overheads. Originally, the per-boot
database was in SQLite with the intention of living in a temporary file
to allow keystore2 to restart without losing auth token state. Since
keystore2 is not allowed to crash, it was moved to an in-memory SQLite
database. Since it is no longer vfs backed, we do not need to pay the
memory, speed, and complexity costs of SQLite for it any longer.

Bug: 186436093
Test: atest keystore2_test
Test: atest CtsKeystoreTestCases
Change-Id: I5c219d294af1876a18a7fdef40307f3b92ae4b8b
diff --git a/keystore2/src/globals.rs b/keystore2/src/globals.rs
index c492120..8d39b22 100644
--- a/keystore2/src/globals.rs
+++ b/keystore2/src/globals.rs
@@ -61,8 +61,7 @@
     .expect("Failed to open database.");
     DB_INIT.call_once(|| {
         log::info!("Touching Keystore 2.0 database for this first time since boot.");
-        db.insert_last_off_body(MonotonicRawTime::now())
-            .expect("Could not initialize database with last off body.");
+        db.insert_last_off_body(MonotonicRawTime::now());
         log::info!("Calling cleanup leftovers.");
         let n = db.cleanup_leftovers().expect("Failed to cleanup database on startup.");
         if n != 0 {