Get 'import gc' working

I guess a number of tests do this to help with testing

from_cpython/Modules/gcmodule.c

@@ -1431,6 +1431,8 @@ initgc(void)
         tmod = PyImport_ImportModuleNoBlock("time");
         if (tmod == NULL)
             PyErr_Clear();
+        else
+            PyGC_RegisterStaticConstant(tmod);
     }
 
 #define ADD_INT(NAME) if (PyModule_AddIntConstant(m, #NAME, NAME) < 0) return

test/tests/closure_ics_test.py

-# expected: reffail
 # Regression test: this triggers a bug in the way we guard for boxedfunctions and their closures.
 # In particular, we guard on the specific value of a BoxedFunction to say that it is the same, but
 # it's possible for the function to get destructed and then a new (and different) boxedfunction to

test/tests/file_destructor.py

-# expected: reffail
 import gc
 
 def open_lots_of_files():

test/tests/finally_except.py

-# expected: reffail
 # these may seem pointless, but they exercise a family of corner cases in our
 # CFG generation pass (cfg.cpp).
 def returner():

test/tests/select_test.py

-# expected: reffail
 import gc
 import select
 

test/tests/testing_helpers.py

-# expected: reffail
 # This file isn't really meant to be run as a test, though it won't really
 # make a difference.
 

test/tests/weakref1.py

-# expected: reffail
 import weakref
 import gc
 

test/tests/weakref_ref_subclass.py

-# expected: reffail
 # Make sure we can subclass from weakref.ref, since the weakref module itself does this
 
 from weakref import ref