Fix stdout capturing problem.

src/evaluation/testing_utils_codeforces.py

@@ -229,6 +229,8 @@ def run_test(code, inputs, outputs, timeout: int = 6000, debug=True, add_extra_i
     new_test = "stdin = sys.stdin\nstdout = sys.stdout\n"
     new_test += '__name__="__main__"\n'
     new_test += "def code():\n"
+    new_test += "\tstdin = sys.stdin\n\tstdout = sys.stdout\n"
+
     for line in code_lines:
         new_test += line