Bug 1558667 - Try to make test_resource_monitor.py more robust; r=ahal

This test has been failing, infrequently, mostly on osx/py2, for many months.
Increasing the time interval between events appears to reduce failure frequency.

Differential Revision: https://phabricator.services.mozilla.com/D76402

testing/mozbase/mozsystemmonitor/tests/test_resource_monitor.py

@@ -88,7 +88,7 @@ class TestResourceMonitor(unittest.TestCase):
 
         t0 = time.time()
         monitor.record_event('t0')
-        time.sleep(0.5)
+        time.sleep(2)
 
         monitor.record_event('t1')
         time.sleep(0.5)