[3.12] gh-116764: Fix regressions in urllib.parse.parse_qsl() (GH-116801) (GH-116894)

* Restore support of None and other false values.
* Raise TypeError for non-zero integers and non-empty sequences.

The regressions were introduced in gh-74668
(bdba8ef42b).
(cherry picked from commit 1069a462f6)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Lib/urllib/parse.py

@@ -773,7 +773,11 @@ def parse_qsl(qs, keep_blank_values=False, strict_parsing=False,
         def _unquote(s):
             return unquote_plus(s, encoding=encoding, errors=errors)
     else:
-        qs = bytes(qs)
+        if not qs:
+            return []
+        # Use memoryview() to reject integers and iterables,
+        # acceptable by the bytes constructor.
+        qs = bytes(memoryview(qs))
         if isinstance(separator, str):
             separator = bytes(separator, 'ascii')
         eq = b'='