compiler: don't emit SyntaxWarning on const stmt

Issue #26204: the compiler doesn't emit SyntaxWarning warnings anymore when
constant statements are ignored.

Lib/test/test_grammar.py

@@ -7,7 +7,6 @@ import unittest
 import sys
 # testing import *
 from sys import *
-from test import support
 
 
 class TokenTests(unittest.TestCase):
@@ -425,11 +424,8 @@ class GrammarTests(unittest.TestCase):
     # Tested below
 
     def test_expr_stmt(self):
-        msg = 'ignore constant statement'
-        with support.check_warnings((msg, SyntaxWarning)):
-            exec("1")
-
         # (exprlist '=')* exprlist
+        1
         1, 2, 3
         x = 1
         x = 1, 2, 3