bpo-43121: Fix incorrect SyntaxError message for missing comma (GH-24436)

diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
index 6068dd9..70dd22c 100644
--- a/Lib/test/test_syntax.py
+++ b/Lib/test/test_syntax.py
@@ -246,9 +246,25 @@
 Traceback (most recent call last):
 SyntaxError: did you forget parentheses around the comprehension target?
 
->>> {x,y: None for x,y in range(100)}
+# Missing commas in literals collections should not
+# produce special error messages regarding missing
+# parentheses
+
+>>> [1, 2 3]
 Traceback (most recent call last):
-SyntaxError: did you forget parentheses around the comprehension target?
+SyntaxError: invalid syntax
+
+>>> {1, 2 3}
+Traceback (most recent call last):
+SyntaxError: invalid syntax
+
+>>> {1:2, 2:5 3:12}
+Traceback (most recent call last):
+SyntaxError: invalid syntax
+
+>>> (1, 2 3)
+Traceback (most recent call last):
+SyntaxError: invalid syntax
 
 From compiler_complex_args():