Revert "Small test sql fixes (#30)" (#31)

This reverts commit 9ce6d75.

Author: ethanyzhang

benchmarks/test/my_post_stage_script.py

@@ -1,6 +1,5 @@
 import sys
 from utils import increment_file_value
-import os
 
 # Main function to handle the command-line argument
 if __name__ == "__main__":

benchmarks/test/stage_4.sql

@@ -1,3 +1,3 @@
 select 'query 6'
-from region;
+from foo;
 select 'query 7';

benchmarks/test/stage_6.sql

@@ -1,4 +1,4 @@
-select c, sum(a) as sum, count(*) as count, max(b) as max
+select c, sum1(a) as sum, count(*) as count, max(b) as max
 from (values (1, 2, 'shanghai'),
              (3, 4, 'dalian'),
              (5, 6, 'new york'),