migration: Fix squashing tables defined as a row value
Created by: efritz
API docs defined a series of objects composed of counting tables (CREATE TABLE counter AS SELECT COUNT(*) FROM ...
) and triggers to update those counts.
Squashing these currently fail unit tests. Because the pre-squashed migration actually inserted an initial row value into the table, we must do the same thing in the squashed migration.
Test plan
This code only modifies the migration squash utility.