don't test js test groups by default

since they are huge and slow, treat the like parallel (also huge and slow)

IPython/testing/iptestcontroller.py

@@ -306,9 +306,11 b' def prepare_controllers(options):'
             js_testgroups = [g for g in testgroups if g not in py_testgroups]
     else:
         py_testgroups = py_test_group_names
-        js_testgroups = all_js_groups()
         if not options.all:
+            js_testgroups = []
             test_sections['parallel'].enabled = False
+        else:
+            js_testgroups = all_js_groups()
 
     c_js = [JSController(name) for name in js_testgroups]
     c_py = [PyTestController(name, options) for name in py_testgroups]