* build schema cache function without db setup

The setup shouldn't happen for sync. The database is already setup by the instance which generated the event. This means that the sync is now faster.

* use SQL loop to drop hdb_views schema views and routines with ordering

This avoids deadlocks when schema is being changed concurrently

* schema sync now only processes the latest event

This becomes useful when a lot of schema change
events happen while we are still processing an
earlier event.

…ror (#2098)

<!-- The PR description should answer 2 important questions: -->

### What

`Built-in operators require a boolean expression type` shows up as an
internal error, when it's really because a boolean expression type
hasn't been provided for a type. Change the type to reflect this, and
include the object type name in question to make it easier to fix.

V3_GIT_ORIGIN_REV_ID: 89fae7521fd9fe1135bfb5c8c9d44c07fc1d93cb