Make timing work with jupyterlite

JupyterLite has a resource, but not getrusage(). This make the code a little more general.

IPython/utils/timing.py

@@ -23,6 +23,11 b' import time'
 # If possible (Unix), use the resource module instead of time.clock()
 try:
     import resource
+except ImportError:
+    resource = None
+
+# Some implementations (like jyputerlite) don't have getrusage
+if resource not None and hasattr(resource, "getrusage"):
     def clocku():
         """clocku() -> floating point number