Bug 1239939 - [mozsystemmonitor] Reduce poll interval on exit r=wlach

Currently we poll at an interval of 1 second when shutting down
mozsystemmonitor. This causes a noticeable shutdown delay on short
running processes. Reducing the interval to 0.1 reduces this delay without
seeming to have any adverse effects.

--HG--
extra : rebase_source : da59ee8d09ada188d011e3a7138b30d91850aacd

testing/mozbase/mozsystemmonitor/mozsystemmonitor/resourcemonitor.py

@@ -286,7 +286,7 @@ class SystemResourceMonitor(object):
 
         done = False
 
-        while self._pipe.poll(1):
+        while self._pipe.poll(0.1):
             start_time, end_time, io_diff, cpu_diff, cpu_percent, virt_mem, \
                 swap_mem = self._pipe.recv()