This commit fixes how one-line async-defs and defs are tracked
by tokenizer. It allows to correctly parse invalid code such
as:
>>> async def f():
... def g(): pass
... async = 10
and valid code such as:
>>> async def f():
... async def g(): pass
... await z
As a consequence, is is now possible to have one-line
'async def foo(): await ..' functions:
>>> async def foo(): return await bar()
Yury Selivanov