bpo-40939: Remove some extra references to PYTHONOLDPARSER (GH-20815)

Automerge-Triggered-By: @pablogsal

Programs/_testembed.c

@@ -485,8 +485,6 @@ static int test_init_from_config(void)
 
     config.install_signal_handlers = 0;
 
-    putenv("PYTHONOLDPARSER=1");
-
     /* FIXME: test use_environment */
 
     putenv("PYTHONHASHSEED=42");
@@ -673,7 +671,6 @@ static void set_most_env_vars(void)
     putenv("PYTHONNOUSERSITE=1");
     putenv("PYTHONFAULTHANDLER=1");
     putenv("PYTHONIOENCODING=iso8859-1:replace");
-    putenv("PYTHONOLDPARSER=1");
     putenv("PYTHONPLATLIBDIR=env_platlibdir");
 }
 

Tools/scripts/run_tests.py

@@ -25,9 +25,8 @@ def main(regrtest_args):
             '-u',                 # Unbuffered stdout and stderr
             '-W', 'default',      # Warnings set to 'default'
             '-bb',                # Warnings about bytes/bytearray
+            '-E',                 # Ignore environment variables
             ]
-    if 'PYTHONOLDPARSER' not in os.environ:
-        args.append('-E')         # Ignore environment variables
 
     # Allow user-specified interpreter options to override our defaults.
     args.extend(test.support.args_from_interpreter_flags())