[reivilibre]

Broken out of #20027 because I'd like to have it land first.

It seems a lot of time in our trial tests goes towards setting up the database. (The same is probably true of Complement too)

We haven't done a full schema for about 20 schema versions, so no surprise!

As a result, I want to produce a full schema soon.

When running make_full_schema.sh, these drop statements now cause the error:

Parse error near line 2: table event_search_content may not be dropped
Parse error near line 3: table event_search_segments may not be dropped
Parse error near line 4: table event_search_segdir may not be dropped
Parse error near line 5: table event_search_docsize may not be dropped
Parse error near line 6: table event_search_stat may not be dropped
Parse error near line 7: table user_directory_search_content may not be dropped
Parse error near line 8: table user_directory_search_segments may not be dropped
Parse error near line 9: table user_directory_search_segdir may not be dropped
Parse error near line 10: table user_directory_search_docsize may not be dropped
Parse error near line 11: table user_directory_search_stat may not be dropped

It seems SQLite has cracked down on code that edits the internal tables.

Because SQLite dumps the schema with CREATE TABLE IF NOT EXISTS for these virtual tables, it's harmless to leave them in the schema dump.

1. make_full_schema: no longer drop sqlite internal tables