Fix when last rowgroup is not same size as first

...change test data to use 99 rows, so that when we have
rowgroup size 10 we exercise this code.

parquet-generator/create-pg-db

@@ -46,7 +46,7 @@ CREATE OR REPLACE FUNCTION datetime(INT8, TEXT) RETURNS TEXT AS \$\$
 
 CREATE OR REPLACE FUNCTION printf(TEXT, DOUBLE PRECISION) RETURNS TEXT AS \$\$
   BEGIN
-    RETURN CAST(\$2 AS DECIMAL(10, 4))::TEXT;
+    RETURN CAST(\$2 AS DECIMAL(10, 2))::TEXT;
   END;
 \$\$ LANGUAGE 'plpgsql' IMMUTABLE;
 EOF