[IMP] tests: disable a few more chrome things

* disable background networking like GoogleUrlTracker ...
  see https://codereview.chromium.org/3312014

* disable backgrounding occluded windows is a CLI swith that was
specifically written for tests to avoid non deterministic behavior.  To
avoid test flakiness, it should come with disable renderer-backgrounding
and disable background-throttling as stated here:
https://github.com/smooth-code/jest-puppeteer/issues/137

* disable breakpad is used to disable crash reporting, the difference
with disable crash-reporter is not clear.
see https://peter.sh/experiments/chromium-command-line-switches/

* disable defaults-apps, prevent installation of default apps on the
first run

* disable dev-shm usage that may cause crashes

odoo/tests/common.py

@@ -578,6 +578,17 @@ class ChromeBrowser():
             '--no-default-browser-check': '',
             '--no-first-run': '',
             '--disable-extensions': '',
+            '--disable-background-networking' : '',
+            '--disable-background-timer-throttling' : '',
+            '--disable-backgrounding-occluded-windows': '',
+            '--disable-renderer-backgrounding' : '',
+            '--disable-breakpad': '',
+            '--disable-client-side-phishing-detection': '',
+            '--disable-crash-reporter': '',
+            '--disable-default-apps': '',
+            '--disable-dev-shm-usage': '',
+            '--disable-device-discovery-notifications': '',
+            '--disable-namespace-sandbox': '',
             '--user-data-dir': self.user_data_dir,
             '--disable-translate': '',
             '--window-size': self.window_size,