Fix lazy module __setattr__ NameError on Python 2.7

Bypass lazy proxy's custom __setattr__ when setting asyncio.coroutine
during _coconut class body, since _coconut is not yet defined.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: evhub

coconut/compiler/header.py

@@ -772,7 +772,7 @@ def _coconut_trollius_coroutine(func):
         def raise_import_error(*args, **kwargs):
             raise err
         return raise_import_error
-asyncio.coroutine = _coconut_trollius_coroutine
+types.ModuleType.__setattr__(asyncio, "coroutine", _coconut_trollius_coroutine)
 asyncio_Return = _coconut_lazy_module("trollius", attr="Return")
             ''',
             if_ge='''