[3.7] bpo-36492: Fix passing special keyword arguments to some functions. (GH-12637) (GH-12645)

The following arguments can be passed as keyword arguments for passing
to other function if the corresponding required argument is passed as
positional:

- "func" in functools.partialmethod(), weakref.finalize(),
  profile.Profile.runcall(), cProfile.Profile.runcall(),
  bdb.Bdb.runcall(), trace.Trace.runfunc() and
  curses.wrapper().
- "function" in unittest.addModuleCleanup() and
  unittest.TestCase.addCleanup().
- "fn" in the submit() method of concurrent.futures.ThreadPoolExecutor
  and concurrent.futures.ProcessPoolExecutor.
- "callback" in contextlib.ExitStack.callback(),
  contextlib.AsyncExitStack.callback() and
  contextlib.AsyncExitStack.push_async_callback().
- "c" and "typeid" in multiprocessing.managers.Server.create().
- "obj" in weakref.finalize().

(cherry picked from commit 42a139ed88c487f325a241c6ee8b308b3c045975)
diff --git a/Lib/trace.py b/Lib/trace.py
index 0ed7ba9..206bd2b 100755
--- a/Lib/trace.py
+++ b/Lib/trace.py
@@ -452,7 +452,19 @@
                 sys.settrace(None)
                 threading.settrace(None)
 
-    def runfunc(self, func, *args, **kw):
+    def runfunc(*args, **kw):
+        if len(args) >= 2:
+            self, func, *args = args
+        elif not args:
+            raise TypeError("descriptor 'runfunc' of 'Trace' object "
+                            "needs an argument")
+        elif 'func' in kw:
+            func = kw.pop('func')
+            self, *args = args
+        else:
+            raise TypeError('runfunc expected at least 1 positional argument, '
+                            'got %d' % (len(args)-1))
+
         result = None
         if not self.donothing:
             sys.settrace(self.globaltrace)