Workaround PGQuery.parse segfault again

This was causing problems again
https://gitlab.com/gitlab-org/gitlab/-/issues/342857 . We have taken the
same approach that was taken in
https://gitlab.com/gitlab-org/gitlab/-/blob/3b3dce4acc82e58fef7d2eccc80236061348c5a4/spec/support/database/prevent_cross_joins.rb#L39

spec/support/database/prevent_cross_database_modification.rb

@@ -79,8 +79,17 @@ module Database
 
       return if cross_database_context[:transaction_depth_by_db].values.all?(&:zero?)
 
+      # PgQuery might fail in some cases due to limited nesting:
+      # https://github.com/pganalyze/pg_query/issues/209
+      #
+      # Also, we disable GC while parsing because of https://github.com/pganalyze/pg_query/issues/226
+      begin
+        GC.disable
         parsed_query = PgQuery.parse(sql)
         tables = sql.downcase.include?(' for update') ? parsed_query.tables : parsed_query.dml_tables
+      ensure
+        GC.enable
+      end
 
       return if tables.empty?