tests/extmod/time_res.py: Properly skip functions not in time module.

If `time.time` doesn't exist, it tries to use `globals()['time']` which is
the time module itself, and that causes the test to fail.  Instead it
should just skip `time.time`.

Signed-off-by: Damien George <damien@micropython.org>

tests/extmod/time_res.py

@@ -37,9 +37,12 @@ def test():
         time.sleep_ms(100)
         for func_name, _ in EXPECTED_MAP:
             try:
-                time_func = getattr(time, func_name, None) or globals()[func_name]
+                if func_name.endswith("_time"):
+                    time_func = globals()[func_name]
+                else:
+                    time_func = getattr(time, func_name)
                 now = time_func()  # may raise AttributeError
-            except (KeyError, AttributeError):
+            except AttributeError:
                 continue
             try:
                 results_map[func_name].add(now)