ast-check "for" is a loop; sync "withas" test ..

with decompyle3.

test/simple_source/stmts/04_withas.py

@@ -17,6 +17,20 @@ def withas_bug(self, nested, a, b):
         with nested(a(), b()) as (x, y):
                 1 // 0
 
+# From 3.7.7 test_functools.py
+# Bug is a unreachable code after "return"
+def test_invalid_registrations(x):
+    return
+    with x:
+        x = 1
+
+# From 3.7.7 test_re.py
+# Bug was hooking in c_with.
+def test_re_tests(tests):
+    for t in tests:
+        with a:
+            continue
+
 # Adapted from 3.8 distutils/command/config.py
 # In 3.8 the problem was in handling "with .. as" code
 def _gen_temp_sourcefile(x, a, headers, lang):