Simplify stream_output (#2398)

python/sglang/test/test_utils.py

@@ -720,13 +720,13 @@ def run_and_check_memory_leak(
 
     # Clean up everything
     kill_process_tree(process.pid)
-    kill_process_tree(process.pid)
     stdout.close()
     stderr.close()
     if os.path.exists(STDOUT_FILENAME):
         os.remove(STDOUT_FILENAME)
     if os.path.exists(STDERR_FILENAME):
         os.remove(STDERR_FILENAME)
+    kill_process_tree(process.pid)
     t.join()
 
     # Assert success
@@ -734,7 +734,7 @@ def run_and_check_memory_leak(
     has_leak = False
     has_abort = False
     for line in output_lines:
-        if "The server is fired" in line:
+        if "Uvicorn running" in line:
             has_new_server = True
         if "leak" in line:
             has_leak = True