test: rename SABjson inputs with file extension .SABjson

test/schedconf/fb_user_think_time_only.json

-{"users": [{"name": "fb_user_think_time_only", "category": "fb_user_think_time_only", "param": {"input_json": "test/workloads/SABjson/load_platform.json"}}]}
\ No newline at end of file
+{"users": [{"name": "fb_user_think_time_only", "category": "fb_user_think_time_only", "param": {"input_json": "test/workloads/SABjson/load_platform.SABjson"}}]}
\ No newline at end of file

test/test_fb_users.py

@@ -33,7 +33,7 @@ def launch_fb_test(user_category, test_input):
         file_path=f'test/schedconf/{user_category}.json',
         user_name=user_category,
         user_category=user_category,
-        input_json=f"test/workloads/SABjson/{test_input}.json")
+        input_json=f"test/workloads/SABjson/{test_input}.SABjson")
 
     out_dir = run_user(user_category, two_machine_platform,
                        empty_workload, test_name=f'{user_category}-{test_input}')