test(load): reduce num of tables in errors loadtest

The table not found error only generates hint when the total number of
tables in a schema are less than 500.

Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>

test/load/errors.sql

@@ -1,7 +1,7 @@
 \ir fixtures.sql
 
 SELECT format('CREATE TABLE test.actors_%s ();', n)
-FROM generate_series(1, 20000) n
+FROM generate_series(1, 450) n -- 500 is the upper limit for table not found error hint generation
 \gexec
 
 -- TODO add many function for fuzzy search (somehow this is making the loadtest start slow)